Little is known about the burden of rheumatoid arthritis (RA) in South Africa. The aim of this study was to establish the prevalence of RA and coexisting chronic disease list (CDL) conditions in the private health sector of South Africa.
A retrospective, cross-sectional analysis was performed on medicine claims data from 1 January 2014 to 31 December 2014 to establish the prevalence of RA. The cohort of RA patients was then divided into those with and those without CDL conditions, to determine the number and type of CDL conditions per patient, stratified by age group and gender.
A total 4352 (0.5%) patients had RA, of whom 69.3% (3016) presented with CDL conditions. Patients had a median age of 61.31 years (3.38; 98.51), and 74.8% were female. Patients with CDL conditions were older than those patients without (p < 0.001; Cohen's d = 0.674). Gender had no influence on the presence of CDL conditions (p = 0.456). Men had relatively higher odds for hyperlipidemia (OR 1.83; CI 1.33-2.51; p < 0.001) and lower odds for asthma (OR 0.83; CI 0.48-1.42; p = 0.490) than women. In combination with hyperlipidemia, the odds for asthma were reversed and strongly increased (OR 6.74; CI 2.07-21.93; p = 0.002). The odds for men having concomitant hyperlipidemia, hypertension, type 2 diabetes mellitus and hypothyroidism were insignificant and low (OR 0.40; CI 0.16-1.02; p = 0.055); however, in the absence of hypothyroidism, the odds increased to 3.26 (CI 2.25-4.71; p < 0.001).
Hypothyroidism was an important discriminating factor for comorbidity in men with RA. This study may contribute to the body of evidence about the burden of RA and coexisting chronic conditions in South Africa.