Table 1

Basic information and characteristics of included studies

Author/yearCountry
(ies)
Geographic region (if in UK)Type of studyTotal sample size% femaleMean age (years)Comorbidities (where studied in the cohort)Average duration of rheumatoid arthritis (months/years, as specified)
Alarcón32 2014Chile.Cross-sectional18990.554.3..
Andersson19 2013Sweden.Cohort14606854.2.6.7 months
Baldassari26 2014USA.Cross-sectional93786.654.6Clinical Comorbidity Index based on 23 doctor-diagnosed conditions111 months (within eRA 6.6)
Barton27 2011USA.Cross-sectional4988454.10 years
Berkanovic28 1996USA.Cross-sectional1187551.7Mean no of comorbidities 1.05, range 0–5.
Brekke20 1999Norway.Cross-sectional247 (respondents); 133 assessed in clinic78.7 in respondents; 82.4 in clinic sample63.2 in respondents; 67.8 in clinic sampleMean 1.1 in respondents12.7 months in respondents; 14.5 months in clinic sample
Callhoff21 2017Germany.Cross-sectional149281.654.9.14 years
Camacho15 2012UK.Cohort (Norfolk Arthritis Register; NOAR)55362.857.2.5 months
Chandrashekara36 2018India.Cross-sectional199083.348.65Recorded as either present or absent: bronchial asthma, chronic heart failure, diabetes mellitus, hypertension, hypercholesterolaemia and thyroid illness. Occurrence of any one of the comorbidities was classified as ‘presence of comorbidity’.
Glave-Testino33 1994Mexico.Case–control128.45Patients with severe comorbidty excluded. Defined as: systemic arterial HTN, chronic renal failure, CHF, chronic liver disease, DM12 years
Gamboa-Cárdenas34 2019Peru.Cohort49885.145.9.5.3 months (symptom duration)
Gong37 2016China.Cross-sectional20785.549Persons with cognitive impairment or current severe diseases, such as cancer and stroke, were excluded. About one quarter of the participants (24.6%) had at least one comorbid disease, such as hypertension (5.8%), digestive system disorders (3.9%), heart disease (2.4%) and anaemia (1.9%).9.3 years
Hallert22 2015Sweden.CohortCohort 1 (1996–98): 317; Cohort 2 (2006–9) 43667%; 68%56; 58..
Harrison16 2009UK.Cohort (NOAR)13936755.5 months
Harrison1 2005UKStoke on Trent; Cannock Chase; Truro; King’s College Hospital, London; and MacclesfieldRCT4666862.1Comorbidity information collected at baseline. Conditions grouped according to body system: cardiovascular disease including hypertension, psychiatric including depression, respiratory, endocrine, gastrointestinal, nervous system.11 years
Jacobi4 2003The Netherlands.Cohort8697159.5.8.7 years
Jiang40 2015Sweden.Cohort30217254.5.6.5 months
Kearsley-Fleet17 2018UKBSRBR-RACohort13 5027657Categorised as 1, 2, 3+10 years
Linde23 2009Denmark.Cohort31567564.5Categorised as 1, 2, 3+7.5 months
Massardo35 2012Chile.Cohort1093; 1059 when excluding those with missing ethnic data85.545.6.6 months
McEntegart2 1997UKScotland (divided whole and west), England, WalesCohort440 in 1980s cohort; 374 in 1993 cohort.57.5..
Molina29 2015USA.Cohort120975.858.10.7 months (average of the three SES categories)
Moufarrej30 2015USA.Cross-sectional18276.345.6 (DAS28≤3.2); 48.5 (DAS28>/=3.2)..
Putrik39 2016MultinationalMultinational cohortCohort39208256RDCI based on: ischaemic cardiovascular disease (myocardial infarction, stroke), cancer (colon, skin, lung, breast and uterus for women, prostate for men and lymphoma), gastrointestinal diseases (diverticulitis, ulcers), infections (hepatitis), lung disease (chronic obstructive pulmonary disease and asthma) and psychiatric disorders (depression).
Roodenrijs24 2020The Netherlands.Cohort152 (52 D2T)72.560.2 D2T; 64.5 non-D2TEULAR comorbidity domains and Charlson Comorbidity Index17 years D2T;
14 years non-D2T
Vliet Vlieland25 1994The Netherlands.Cohort/ cross-sectional12710035.9 (disease onset).1.5 year (at diagnosis)
Yang31 2015Canada.Cohort20237352.86.6.1 months
Yates18 2021UKNEIAACohort745562.356.740.2% ≥1 comorbidity.
Young3 2000UKMultipleCohort86965.156 (median).6 months (median)
Zou38 2020Singapore.Cohort21373.251.3Charlson Comorbidity Index, mean 1.11.8 months
  • CHF, Congestive Heart Failure; DAS, Disease Activity Score; DM, Diabetes Mellitus; EULAR, European Alliance of Associations for Rheumatology; HTN, Hypertension; RCT, Randomised Controlled Trial; RDCI, Rheumatic Disease Comorbidity Index; SES, Socioeconomic Status.