Association between hypothyroidism and elderly-onset rheumatoid arthritis: A cross-sectional study at national hospital in Peru

Abstract

Objective

To determine the association between hypothyroidism and elderly-onset rheumatoid arthritis (EORA).

Methods

A cross-sectional study was performed including patients with rheumatoid arthritis at the Adolfo Guevara Velasco National Hospital, Cusco, Peru in 2024. The outcome was EORA, defined as disease onset after 60 years old. The exposure was a history of hypothyroidism, and the following covariates were considered: sex, smoking, family history of autoimmune disease in first-degree relatives, rheumatoid factor and anti-CCP levels. The association between hypothyroidism and EORA was assessed using prevalence ratios (PR) with their 95% confidence interval (CI), estimated by generalized linear models with a Poisson family, log link, and robust variance. A p-value <0.05 was considered statistically significant.

Results

A total of 133 patients were included, 14 (10.5%) of whom had EORA. The mean age was 55 ± 12.6 years and 90% were female. Only 8.3% of patients reported a history of hypothyroidism. Hypothyroidism was significantly associated with EORA (adjusted PR 9.03, 95% CI 3.17–26.68). Other factors associated with EORA were disease duration, smoking, the history of autoimmune disease in a first-degree relative, and rheumatoid factor.

Conclusions

A history of hypothyroidism was independently associated with EORA in patients with rheumatoid arthritis from Peru. Screening for hypothyroidism in EORA patients may enhance management and address autoimmune comorbidities.