Cairns et al. BMC Rheumatology (2020) 4:50 https://doi.org/10.1186/s41927-020-00147-2 BMC Rheumatology RESEARCH ARTICLE Open Access The impact of gout as described by patients, using the lens of The International Classification of Functioning, Disability and Health (ICF): a qualitative study Isobel Cairns1, Karen Lindsay2, Nicola Dalbeth2,3, Cesar Díaz-Torné4, Maria Antònia Pou5, Basilio Rodríguez Diez6, Enriqueta Pujol-Ribera7, Charlotte Panter8, Rob Arbuckle8, Sophi Tatlock8 and William J. Taylor1* Abstract Background: The International Classification of Functioning, Disability and Health (ICF) aims to comprehensively describe the ways in which a person’s health condition affects their life. This study aimed to contribute to the development of an ICF core set for gout through patient opinion derived from focus groups and interviews. Methods: We conducted a secondary qualitative analysis of data from three studies investigating the patient experience of gout. In total there were 30 individual interviews and 2 focus groups (N = 17) comprising 47 participants. We conducted thematic analysis of the textual data to extract meaning units, which were then linked to the ICF. Results: A large number of ICF categories were relevant to patients with gout. Participants mentioned 93 third level categories, 17 of which were mentioned by more than 50% of patients. The most references for a single category was for b280, Sensation of pain, followed by personal factors (not yet categorised by the ICF). The most participants mentioned the environmental factor e355, Health professional support, followed by b280, Sensation of pain. Conclusion: The categories identified in this study as relevant to patients with gout highlight the severe pain associated with this disease, the impact on mobility and corresponding life areas. The roles of health professional support, medication, and personal attitudes to disease management are also reflected in the data. These results will contribute to the development of the ICF core set for gout. Keywords: Gout, International classification of functioning, Disability and health, World Health Organisation, Patient outcome assessment, Qualitative research * Correspondence: will.taylor@otago.ac.nz 1 Rehabilitation Teaching and Research Unit, Department of Medicine, University of Otago, PO Box 7343, Wellington, New Zealand Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Cairns et al. BMC Rheumatology (2020) 4:50 Page 2 of 9 Background This study is a qualitative ‘amplified supplementary Once known as the ‘rich man’s disease’, gout is increas- analysis’; more than one data set has been combined to ingly common among older men, where it is the most allow an analysis of an aspect that was partially ad- common inflammatory joint disease [1]. Gout is a meta- dressed in the primary studies – namely patient experi- bolic disease caused by high levels of urate, forming crys- ence of gout – but that supplements these conclusions tals that deposit in joints and periarticular tissues, leading by including a new factor, the ICF [11]. Each individual to painful and debilitating arthritis [2]. Flares are intermit- study received approval from the relevant research ethics tent but markedly painful, and as the disease progresses committee or Institutional Review Board. may become more frequent and tophi (deposits of mono- sodium uric acid crystals) may develop [2]. New Zealand transcripts For the sufferer, gout attacks (or ‘flares’) are not only Ten individual interviews with male gout patients were painful but disabling, leading to a marked decrease in obtained from a study based in South Auckland, NZ mobility and impacting on many life areas, such as em- [10]. The authors used purposive sampling to ensure a ployment [3]. Yet previous means of assessing disability range of ethnicities and experiences, conducting semi- in gout have been problematic because of its episodic structured interviews using a grounded theory method- nature, and because measures may not adequately reflect ology to explore participant experiences of gout, their the impact of gout on lower limb functioning and mobil- understanding of the disease and attitude toward it and ity or sufficiently capture the breadth of the disease im- its treatment. Questions were motivated an overall ques- pact as experienced by the patient [4, 5]. tion of “Why is gout so severe in Counties Manukau?” The International Classification of Functioning, Dis- These included questions about the history of the pa- ability and Health is the World Health Organisation tients’ lifetime experience of gout and pre-disease-onset (WHO) framework for the conceptual understanding of knowledge of gout. health and disability [6]. It classifies the impacts of a dis- ease related to its effect on body functioning, body struc- United States transcripts tures or activities and participation, impacts which may Transcripts were obtained from 20 individual interviews be mediated by the facilitators or barriers offered by a with gout patients (male = 12, female = 8) in Baltimore, person’s physical, social and cultural environment. The New Orleans and St. Louis, USA [9]. Sampling was pur- complete ICF contains over 1000 fourth level categories posive to ensure a range of characteristics, and partici- [6]. This provides a comprehensive overview of the pants were recruited through their rheumatologist or health of an individual but only some of these will be primary care physician. The main motivation for this relevant to a given disease. study was to understand the patient experience of gout The development of ICF core sets is intended to pro- in order to better measure clinical study endpoints or to vide a concise set of categories of functioning related to guide development of a gout-specific outcome measure a particular condition, leading to tools for research and for clinical trial use. The interviews followed a detailed practice that have global applicability [7]. Developing interview guide; the first half of the interview used open- these measures requires input from both health profes- ended questions to explore the participant’s experience sionals and sufferers of the disease. This paper supple- of the disease with a main focus on symptoms and bur- ments the research of Kool et al. by providing a patient den, and the second half involved completion and as- perspective of the impact of gout on various areas of life sessment of patient outcome measures, the Heath as described by the ICF [8]. A core-set of ICF categories Assessment Questionnaire – Disability Index and Gout relevant to people with gout is highly useful to ensure Assessment Questionnaire ‘overall concern’ domain. adequate content coverage of tools and instruments to Each interview was on average 1.5 h long. evaluate outcomes, including patient-reported outcomes, in clinical care, intervention studies and other outcomes Spanish transcripts research. Two focus group transcripts were obtained from a study in Barcelona, Spain. The first focus group was purpos- Methods ively sampled to give a range of age, gender and disease This study was a secondary analysis of data collected by characteristics and had 11 participants (M = 8, F = 3). three primary qualitative studies, conducted in the Participants in the second focus group (N = 6; M = 5 F = United States [9], New Zealand [10] and Spain (not yet 1) were recruited from an outpatient clinic and were se- published). These studies are described in more detail lected consecutively. Each focus group lasted about 2 h below. There were 47 participants in total comprising 30 and 30 min. Discussion prompts included: what causes individual interviews and two focus groups with a total gout, how gout was diagnosed, symptoms of gout, effects of 17 participants. in daily life, experience of treatments, relationships with Cairns et al. BMC Rheumatology (2020) 4:50 Page 3 of 9 health professionals, and societal concepts of gout. Focus the remaining 19 of which denoted negative attributes group discussion was in Castillian and translated into or barriers. See Table 1 for a comprehensive overview. English by a multilingual, native Italian speaker. In addition, 27 initial concepts were linked to the con- cept of personal factors, which are not yet categorised by Analysis the ICF. These were grouped into four main areas: indi- Qualitative data analysis followed the process of mean- vidual attitudes to disease and its management (60% of ing condensation [12]. Familiarity with the transcripts the references in this category), health literacy (19%), from each study was established and meaning units were family experience of gout (12%) and negative attitudes to identified in the data [12]. Concepts were identified seeking care (8%). within each meaning units and were grouped into simi- There were several concepts were not definable by the lar concepts using the analysis software NVivo 11 ICF: co-morbidities, association with ethnicity, commu- (NVivo qualitative data analysis Software; QSR Inter- nity visibility of gout, features of onset, physical (non- national Pty Ltd. Version 11, 2016). For instance, the dietary) triggers, and certain approaches to managing comment, “You can’t walk on it, you know. Even to have pain and disease. Tophi were included as a non- a – the sheet on the bed to touch it is painful” contains definable physical factor. the concepts ‘difficulty walking any distance’ and ‘pain There were 17 categories mentioned by at least 50% of caused from minimum sensation’. An initial sub-set of 2 participants; these categories largely correspond to those transcripts was coded by both coders to establish inter- that received the greatest number of mentions (Table 2). rater reliability. The top five categories mentioned by the most number Each concept was then linked to the most appropriate of participants were: ICF category according to established linking rules [13, e355 Health professionals ++ (98% of participants), eg 14]. The ICF is divided into chapters, or ‘first level’ cat- BM-02: In – one night, it was so severe, I had to go to the egories, which sub-divide the four separate concepts of hospital, because I didn’t have any medicine. And I went body functions, body structures, activities and participa- on – went to XXXX Hospital. They gave me three tablets tion, and environmental factors. Each chapter consists of of Cortisine (sic) – Cortisine (sic) – what – how you pro- a number of ‘second level’ headings, which are made up nounce it – and told me to go see my regular private- of ‘third level’ and then the most detailed ‘fourth level’ care physician, which was Dr. XXXX. And she gave me categories (6). Concepts were linked to the most relevant the same thing. And I’ve been taking it for the last 2 fourth level ICF category if possible. If no such category weeks, but I’m kind of over this bout a – at this time. was appropriate, they were linked to a third level cat- d570 Looking after one’s health -- negative impacts egory, or in some instances, a second level category. (96%), eg BM-03: It g – it got – it got a little better, but There were some concepts that were not able to be even though I don’t eat the beef, I don’t eat the steak, linked to any ICF categories, which were coded as non- guess what? It just falls on you. Something just – just falls definable. me on you, you know, one way or the other. You know, I As an example, the concept ‘difficulty walking any dis- think it’s just – it’s – it’s just falls, you know what I’m tance’ was linked to d4508 Walking, other specified -- saying? Because – b280 Sensation of pain (96%), eg BM- any distance under the third level category, Walking. 04: Because that’s what overrides everything else. I mean ‘Pain caused from minimum sensation’ was linked to the swelling is one thing. I mean you can kind of deal b2702 Sensitivity to pressure, under the third level cat- with that. The – the - uh, the temp – you know the heat- egory, Sensory functions related to temperature and other ing up of the joint, you can kind of deal with that, but stimuli. After concepts had been linked to the ICF the the excruciating pain is – you know, dominates all that. second researcher (WT) confirmed the accuracy of link- e110 Products or substances for personal consumption age decisions in a random subset (10%) of the linked – facilitator, and personal factors. Eg SUBJECT: Well he categories. always tells me don’t eat this, don’t eat that, take these pills because they are the ones and he tried to put me on Results Allopurinol and they did not work because I was had an In total 4897 meaning units were identified across all attack through it so his only alternative was to give me transcripts. These were grouped into 396 initial con- these pills Colchicine and of course it was down the track cepts. These concepts were linked to 93 third level cat- through other friends of mine that told me what Prednis- egories of the ICF. Of these, 17 were in the body one can do to you in the end and it will start eating into functions chapter, 5 in the body structures chapter, 35 your bones or something like that and now I am starting in the activities and participation chapter, and 34 in the to wake up to that. But at the end of the day it was fixing environmental factors chapter, 15 of which denoted fa- the pain and it was no fault of his, if I wanted some I cilitators or positive attributes of the environment, and was going to have to get some for the pain and all that. Cairns et al. BMC Rheumatology (2020) 4:50 Page 4 of 9 Table 1 Linked ICF categories and number of references by data source ICF Category US NZ Spain Total Body functions b body functions 4 8 8 20 b126 Temperament and personality functions 126 10 6 142 b130 Energy and drive functions 32 1 0 33 b134 Sleep functions 56 0 2 58 b140 Attention functions 7 1 0 8 b152 Emotional functions 117 11 3 131 b180 Experience of self and time functions 9 0 0 9 b265 Touch function 22 2 1 25 b270 Sensory functions related to temperature and other stimuli 81 12 7 100 b280 Sensation of pain 413 40 44 497 b298 Sensory functions and pain, other specified -- sensation of paralysis 16 0 0 16 b298 Sensory functions and pain, other specified -- sensation of weakness 10 0 0 10 b525 Defecation functions 7 5 1 13 b535 Sensations associated with the digestive system 2 3 0 5 b710 Mobility of joint functions 55 3 7 65 b755 Involuntary movement reaction functions 5 0 0 5 b770 Gait pattern functions 34 4 6 44 Activity and participation d activities 37 1 3 41 d230 Carrying out daily routine 28 1 0 29 d240 Handling stress and other psychological demands 5 2 3 10 d298 General tasks and demands, other specified -- planning 11 0 0 11 to undertake activities d4 mobility 63 5 8 76 d410 Changing basic body position 102 5 0 107 d415 Maintaining a body position 38 2 1 41 d420 Transferring oneself 28 3 0 31 d430 Lifting and carrying objects 10 0 0 10 d440 Fine hand use 35 1 0 36 d445 Hand and arm use 25 1 1 27 d450 Walking 148 16 8 172 d455 Moving around 33 3 2 38 d460 Moving around in different locations 24 5 4 33 d470 Using transportation 15 2 1 18 d480 Riding animals for transportation 0 1 0 1 d510 Washing oneself 27 1 2 30 d520 Caring for body parts 21 0 0 21 d530 Toileting 1 0 0 1 d540 Dressing 75 3 3 81 d550 Eating 8 0 0 8 d570 Looking after one’s health -- negative impacts 98 74 65 237 d570 Looking after one’s health -- positive impacts 105 59 28 192 d620 Acquisition of goods and services 33 0 0 33 d630 Preparing meals 15 0 0 15 d640 Doing housework 42 0 0 42 d660 Assisting others 10 0 0 10 d750 Informal social relationships 2 0 2 4 Cairns et al. BMC Rheumatology (2020) 4:50 Page 5 of 9 Table 1 Linked ICF categories and number of references by data source (Continued) ICF Category US NZ Spain Total d760 Family relationships 7 8 5 20 d770 Intimate relationships 3 0 0 3 d845 Acquiring, keeping and terminating a job 4 3 1 8 d850 Remunerative employment 67 22 9 98 d870 Economic self-sufficiency 1 2 1 4 d920 Recreation and leisure 34 17 12 63 d930 Religion and spirituality 14 0 0 14 Environmental factors e110 Products or substances for personal consumption -- barrier 49 29 24 102 e110 Products or substances for personal consumption -- facilitator 170 42 32 244 e115 Products and technology for personal use in daily living 42 0 2 44 e120 Products and technology for personal indoor and outdoor 64 3 3 70 mobility and transportation e225 Climate 1 2 0 3 e310 Immediate family -- 0 3 2 5 e310 Immediate family ++ 61 26 8 95 e320 Friends -- 0 1 0 1 e320 Friends ++ 2 3 1 6 e325 Acquaintances, peers, colleagues, neighbours and community 4 0 1 5 members ++ e330 People in positions of authority -- 0 2 0 2 e330 People in positions of authority ++ 2 6 0 8 e355 Health professionals -- 3 30 23 56 e355 Health professionals ++ 92 78 51 221 e355 Health professionals 00 2 3 5 10 e398 Support and relationships, other specified -- absence due to 1 0 0 1 living alone e398 Support and relationships, other specified -- burden of care for 1 6 0 7 immediate family e398 Support and relationships, other specified -- emotional impact 3 3 1 7 for family members e410 Individual attitudes of immediate family members -- 0 3 1 4 e410 Individual attitudes of immediate family members ++ 6 7 1 14 e420 Individual attitudes of friends ++ 2 0 0 2 e420 Individual attitudes of friends 00 1 2 0 3 e425 Individual attitudes of acquaintances, peers, colleagues, 0 3 2 5 neighbours and community members -- e430 Individual attitudes of people in positions of authority -- 0 0 1 1 e430 Individual attitudes of people in positions of authority ++ 3 2 0 5 e450 Individual attitudes of health professionals -- 0 1 0 1 e450 Individual attitudes of health professionals ++ 1 2 0 3 e460 Societal attitudes -- 1 18 10 29 e460 Societal attitudes 00 or ++ 1 4 0 5 e465 Social norms, practices and ideologies 10 15 2 27 e498 Attitudes, other specified -- restauranteurs 0 0 2 2 e570 Social security services, systems and policies ++ 2 0 0 2 e580 Health services, systems and policies -- 6 11 6 23 e580 Health services, systems and policies ++ 2 8 8 18 Body structures s710 Structure of head and neck region 1 0 0 1 Cairns et al. BMC Rheumatology (2020) 4:50 Page 6 of 9 Table 1 Linked ICF categories and number of references by data source (Continued) ICF Category US NZ Spain Total s730 Structure of upper extremity 27 3 2 32 s750 Structure of lower extremity 110 4 8 122 s798 Structures related to movement, other 26 2 1 29 specified -- unspecified joints s810 Structure of areas of skin 20 2 4 26 nd-ph -- tophi 1 4 11 16 personal factors 189 164 86 436 total 3071 829 542 4439 Categories from 17 of the 30 first level chapters of the Participation, and Environmental Factors were split ICF were mentioned by participants (Table 3). The Body roughly evenly, with 30, 39 and 26% of total references Structures chapter was the least common, with only 5% respectively (Table 4). In these first level categories, Sen- of references coded to categories in this chapter; most of sory Functions and Pain was the most common in the this related to Structures Related to Movement. The category of Body Functions; the majority of this was re- other chapters of Body Functions, Activities and lated to b280 Sensation of pain (77% of the references Table 2 Top 20 most mentioned ICF categories (ranked in order of most to fewest mentions) ICF category US (n = 20) NZ (N = 10) Spain (n = 17) Total number of Number of Median number Number of Median number Number of instances instances (% of of instances per instances (% of of instances per instances (% of (% of participants) participant participants) participant participants) participants) b280 Sensation of pain 413 (100) 18.5 40 (100) 4 44 (88) 497 (96) Personal factors 189 (100) 6.5 164 (100) 14 86 (82) 439 (94) e110 Products or substances for 170 (95) 7 42 (100) 4.5 32 (88) 244 (94) personal consumption -- facilitator d570 Looking after one’s health -- 98 (95) 5 74 (100) 7 65 (94) 237 (96) negative impacts e355 Health professionals ++ 92 (100) 5 78 (100) 8 51 (94) 221 (98) d570 Looking after one’s health -- 105 (85) 5 59 (100) 3.5 28 (76) 192 (85) positive impacts d450 Walking 148 (100) 7 16 (80) 1 8 (29) 172 (70) b126 Temperament and personality 126 (95) 6.5 10 (60) 1 6 (41) 142 (68) functions b152 Emotional functions 117 (85) 5.5 11 (80) 1 3 (12) 131 (57) s750 Structure of lower extremity 110 (80) 5.5 4 (20) 0 8 (35) 122 (51) a d410 Changing basic body position 102 5 0 107 e110 Products or substances for 49 (75) 2 29 (90) 3 24 (65) 102 (74) personal consumption -- barrier b270 Sensory functions related to 81 (65) 2.5 12 (60) 1 7 (35) 100 (53) temperature and other stimuli d850 Remunerative employment 67 (80) 2.5 22 (100) 2 9 (41) 98 (70) e310 Immediate family ++ 61 (65) 1 26 (70) 1 8 (41) 95 (57) a d540 Dressing 75 3 3 81 d4 mobility 63 (80) 2 5 (30) 0 8 (29) 76 (51) a e120 Products and technology for 64 3 3 70 personal indoor and outdoor mobility and transportation a b710 Mobility of joint functions 55 3 7 65 d920 Recreation and leisure 34 (70) 2 17 (60) 1.5 12 (41) 63 (57) a were mentioned frequently by fewer than 50% of participants Cairns et al. BMC Rheumatology (2020) 4:50 Page 7 of 9 Table 3 Most referenced ICF categories by percentage of participants number of participants Name us N = 20 nz N = 10 spain N = 17 All total as % of total participants e355 Health professionals ++ 20 10 16 46 98% d570 Looking after one’s health -- negative impacts 19 10 16 45 96% b280 Sensation of pain 20 10 15 45 96% e110 Products or substances for personal consumption -- facilitator 19 10 15 44 94% personal factors 20 10 14 44 94% d570 Looking after one’s health -- positive impacts 17 10 13 40 85% e110 Products or substances for personal consumption -- barrier 15 9 11 35 74% d850 Remunerative employment 16 10 7 33 70% d450 Walking 20 8 5 33 70% b126 Temperament and personality functions 19 6 7 32 68% e310 Immediate family ++ 13 7 7 27 57% d920 Recreation and leisure 14 6 7 27 57% b152 Emotional functions 17 8 2 27 57% b270 Sensory functions related to temperature and other stimuli 13 6 6 25 53% b770 Gait pattern functions 17 3 5 25 53% s750 Structure of lower extremity 16 2 6 24 51% d4 mobility 16 3 5 24 51% d455 Moving around 19 2 2 23 49% e355 Health professionals -- 3 7 12 22 47% d activities 16 1 5 22 47% for this chapter), followed by Temperament and person- The frequency of references to categories related spe- ality functions (37%). Mobility and Self-Care were the cifically to looking after one’s health under self-care re- most common in the category of Activities, with Walk- flects that the discussion of gout frequently touched on ing the most common third-level category affected in what triggered gout flares for participants and how they Mobility (29%) and d570 Looking after one’s health -- attempted to manage these triggers. For an individual negative impacts in Self-Care (42%). In the category of what triggers a gout flare, such as particular foods, may Environmental Factors, Products and Technology and not be obvious and thus their ability to make healthy Support and Relationships were the most common chap- choices is compromised. Also, avoiding enjoyed foods ters, with e110 Products or substances for personal con- because they are triggers may be difficult for patients. sumption – facilitator as the most common for the first The importance of factors related to self-management of (53%) and e355 Health professionals ++ as the most the disease is also reflect in the frequency of meaning common for the second (52%). units coded under the (so far unspecified) ‘personal fac- tors’ category of the ICF. Environmental factors were an important feature for Discussion participants, both positive and negative – sometimes for The ICF categories discussed by participants indicate the same category. For example, pharmaceutical treat- that the most common bodily impacts of gout for pa- ments for gout were a facilitator for many participants tients are related to pain. Body structures most affected but for others medication was ineffective or caused un- were swelling of areas related to movement. Given this, pleasant side effects. Another factor was the support of it is not surprising that the activity described most often health professionals, which could act as a facilitator as compromised was mobility, followed by self-care, but when it was present, or a barrier when it was not – for also including major life areas, particularly employment, example, lack of communication about the importance domestic life and recreation. The impact of pain and of managing the disease, or failure to refer on to more limits on activity and mobility lead to impairments in specialist care. mental and emotional function, as indicated by the num- There was significant crossover between the frequency ber of references to temperament and emotions. of ICF categories across study locations, but also some Cairns et al. BMC Rheumatology (2020) 4:50 Page 8 of 9 Table 4 Distribution of affected ICF categories Number of instances % of total references US NZ Spain All b1 CHAPTER 1 MENTAL FUNCTIONS 347 23 11 381 10% b2 CHAPTER 2 SENSORY FUNCTIONS AND PAIN 542 54 52 648 17% b5 CHAPTER 5 FUNCTIONS OF THE DIGESTIVE, METABOLIC AND ENDOCRINE SYSTEMS 9 8 1 18 0% b7 CHAPTER 7 NEUROMUSCULOSKELETAL AND MOVEMENT-RELATED FUNCTIONS 94 7 13 114 3% Total 1161 30% s7 CHAPTER 7 STRUCTURES RELATED TO MOVEMENT 164 9 11 184 5% s8 CHAPTER 8 SKIN AND RELATED STRUCTURES 20 2 4 26 1% Total 210 5% d2 CHAPTER 2 GENERAL TASKS AND DEMANDS 44 3 3 50 1% d4 CHAPTER 4 MOBILITY 521 44 25 590 15% d5 CHAPTER 5 SELF-CARE 335 137 98 570 15% d6 CHAPTER 6 DOMESTIC LIFE 100 0 0 100 3% d7 CHAPTER 7 INTERPERSONAL INTERACTIONS AND RELATIONSHIPS 12 8 7 27 1% d8 CHAPTER 8 MAJOR LIFE AREAS 72 27 11 110 3% d9 CHAPTER 9 COMMUNITY, SOCIAL AND CIVIC LIFE 48 17 12 77 2% Total 1524 39% e1 CHAPTER 1 PRODUCTS AND TECHNOLOGY 325 74 61 460 12% e3 CHAPTER 3 SUPPORT AND RELATIONSHIPS 171 161 92 424 11% e4 CHAPTER 4 ATTITUDES 25 57 19 101 3% e5 CHAPTER 5 SERVICES, SYSTEMS AND POLICIES 10 19 14 43 1% Total 1028 26% differences. It is a limitation of the study that such dif- did mean that coding was consistent across the 3 data ferences cannot be attributed to local culture but may sources. have been influenced by the research protocol used in The concepts elicited from patients in these various each location. Yet, the diversity of these patient groups studies cohere with previous investigations of the impact and the large sample size is also one of the strengths of of gout on the life of patients, particularly the impact of this study. affected lower limbs on mobility and other activities and That this study was a secondary analysis of existing taking time off work (3,4). Kool et al. found that out- qualitative data is a limitation, as control could not be come studies particularly failed to assess the ICF compo- exercised over the collection of information to cover the nents of ‘Activity and participation’ and ‘Environmental ICF comprehensively with each participant. Different re- factors’, both of which were found to be particularly search objectives for each study meant that although relevant to participants in this study (8). The results of there was a large quantity of data that was elicited in an this study contribute to the process of developing an unbiased manner, not all of it was relevant to the ICF. ICF Core Set for gout (7,8). There are also issues combining studies with different methodologies – methodology is used to establish rigour and concepts such as ‘data saturation’, that indicate Conclusions when the sample size is appropriate for the study. Be- In this multi-country qualitative study, we found that a cause this concept was not under our control, the data large number of ICF categories are relevant to people was possibly ‘oversaturated’ – leading to excessive men- with gout. Pain and personal factors are the most fre- tions of particular concepts while not reflecting the di- quently mentioned ICF categories by people with gout. versity of the experience of gout. Environmental factors are also frequently relevant in- Nearly all the data coding was done by a single obser- cluding dietary and other triggers, and the role of health ver. This is acknowledged as a significant limitation, as professionals. The results of this study will contribute to the coding reliability cannot be calculated. However, it the process of developing an ICF Core Set for gout. Cairns et al. BMC Rheumatology (2020) 4:50 Page 9 of 9 According to the development process recommended Author details 1 by the ICF Research Branch, further research necessary Rehabilitation Teaching and Research Unit, Department of Medicine, University of Otago, PO Box 7343, Wellington, New Zealand. 2Department of to identify a core-set of ICF categories for gout are: (1) Rheumatology, Auckland City Hospital, Auckland, New Zealand. 3Department application of the generic ICF Checklist (https://www. of Medicine, University of Auckland, Auckland, New Zealand. 4Universitat who.int/classifications/icf/icfchecklist.pdf?ua=1) list of Autònoma de Barcelona. Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. 5EAP Encants. Institut Català de la Salut, Barcelona, Spain. 6Unitat de categories to patients with gout and (2) a consensus Reumatologia. Hospital Vall d’Hebró, Barcelona, Spain. 7Institut Universitari workshop of relevant stakeholders to consider all the d’Investigació en Atenció Primària, ICS, Barcelona, Spain. 8Adelphi Values, data from preceding empirical research and to formulate Adelphi Mill, Bollington, Cheshire SK10 5JB, UK. the final core-set. Received: 30 September 2019 Accepted: 19 June 2020 Abbreviations ICF: The International Classification of Functioning, Disability and Health; References NZ: New Zealand; USA: United States of America; WHO: World Health 1. Smith EU, Diaz Torne C, Perez Ruiz F, March LM. Epidemiology of gout: an Organisation update. Best Pract Res Clin Rheumatol. 2010;24(6):811–27. 2. Taylor WJ, Grainger R. Clinical features of gout. In: Terkeltaub R, editor. Gout Acknowledgements and other crystal arthropathies: Philadelphia, PA: Saunders/Elsevier; 2012. Not applicable. 3. Kleinman NL, Brook RA, Patel PA, et al. The impact of gout on work absence and productivity. Value Health. 2007;10(4):231–7. Authors’ contributions 4. ten Klooster PM, Oude Voshaar MA, Taal E, van de Laar MA. Comparison of The authors read and approved submission of the final manuscript. IC measures of functional disability in patients with gout. Rheumatology analysed the data and wrote the first draft of the manuscript. KL and ND (Oxford). 2011;50(4):709–13. conducted the New Zealand data-source study; CDT, MAP, BRD, EPR con- 5. ten Klooster PM, Vonkeman HE, Voshaar MA, Bode C, van de Laar MA. ducted the Spanish data-source study; CP, RA, ST conducted the US data- Experiences of gout-related disability from the patients' perspective: a source study. WJT conceived the study, obtained funding and contributed to mixed methods study. Clin Rheumatol. 2014;33(8):1145–54. the data analysis and editing of the manuscript. 6. World Health Organization. International classification of functioning, disability and health: ICF. Geneva: WHO; 2001. Authors’ information 7. Cieza A, Ewert T, Ustun TB, Chatterji S, Kostanjsek N, Stucki G. Development Not applicable. of ICF Core sets for patients with chronic conditions. J Rehabil Med. 2004; 36(44 Suppl):9–11. Funding 8. Kool EM, Nijsten MJ, van Ede AE, Jansen TL, Taylor WJ. Discrepancies in how This project was supported by Arthritis New Zealand (grant reference R259 the impact of gout is assessed in outcomes research compared to how to WJT). The US data collection was funded by Pfizer (undertaken health professionals view the impact of gout, using the lens of the commercially by Adelphi Values). The NZ data collection was supported by international classification of functioning, health and disability (ICF). Clin the Maaori Gout Action Group of Counties Manukau District Health Board Rheumatol. 2016;35(9):2259–68. and the Auckland Rheumatology Fund (to KL). The Spanish data were 9. Tatlock S, Rüdell K, Panter C, et al. What outcomes are important for gout collected with the direct support of the authors. The funders had no direct patients? In-depth qualitative research into the gout patient experience to role in the conduct of the reported study, analysis of the data or writing of determine optimal endpoints for evaluating therapeutic interventions. the manuscript. Patient. 2017;10(1):65–79. 10. Lindsay K, Gow P, Vanderpyl J, Logo P, Dalbeth N. The experience and Availability of data and materials impact of living with gout: a study of men with chronic gout using a The datasets generated and/or analysed during the current study are not qualitative grounded theory approach. J Clin Rheumatol. 2011;17(1):1–6. publicly available due to the data consisting of confidential textual 11. Heaton J. Secondary analysis of qualitative data: an overview. Hist Soc Res. transcripts from individual participants. 2008;33(3):33–45. 12. Kvale S. Interviews - an introduction to qualitative research interviewing. Ethics approval and consent to participate California: Sage; 1996. This study reports on a secondary analysis of qualitative data that arose from 13. Cieza A, Geyh S, Chatterji S, Kostanjsek N, Ustun B, Stucki G. ICF linking rules: three individual studies. Each individual study received approval from the an update based on lessons learned. J Rehabil Med. 2005;37(4):212–8. relevant research ethics committee or Institutional Review Board. The NZ 14. Cieza A, Fayed N, Bickenbach J, Prodinger B. Refinements of the ICF linking study was approved by the New Zealand Northern A Health and Disability rules to strengthen their potential for establishing comparability of health Ethics Committee (reference NTY/06/12/136/AM03). The US study was information. Disabil Rehabil. 2019;41(5):574–83. approved and overseen by an Independent Review Board in the US (approval codes: ADE1–14-472, ADE2–14-168). The Spanish study was approved by the Ethic Committee of Clinical Investigation of the Fundació Publisher’s Note de Gestió Sanitaria de l’Hospital de la Santa Creu i Sant Pau (approval Springer Nature remains neutral with regard to jurisdictional claims in number 17/034 (OTROS)). Written informed consent was obtained prior to published maps and institutional affiliations. the collection of any data. Consent for publication Not applicable. Competing interests ND has received consulting fees, speaker fees or grants from Takeda, Ardea, AstraZeneca, Cymabay, Abbvie, and Crealta, outside the submitted work. WT has received consulting fees from Pfizer (NZ) and Janssen-Cilag Pty Ltd., out- side the submitted work. CDT has received consulting fees, speaker fees or grants from AstraZeneca and Grünenthal. BRT declares no conflicts of inter- est. RA, ST and CP are employees of Adelphi Values and as such were contracted by Pfizer to conduct the research; they perform research for many other pharmaceutical companies for payment.