Frequency of thyroid dysfunction among rheumatoid arthritis patients at the Kenyatta National Hospital, Nairobi, Kenya

Abstract

Background: Rheumatoid Arthritis (RA) affects 0.5-1% of the adult population. A higher prevalence of thyroid dysfunction is observed in patients with RA compared to the general population.
Objectives: To establish the frequency of thyroid dysfunction among ambulatory RA patients and to describe the association between thyroid dysfunction and the patients’ socio-demographic characteristics, clinical characteristics, level of disease activity, and their functional status.
Design: This was a cross-sectional descriptive study.
Methods: Adult patients on follow up for RA at the outpatient clinic were sampled. Sociodemographic data was recorded. The Clinical Disease Activity Index (CDAI) and Health Assessment Questionnaire (HAQ) scores were computed from examination findings and questionnaires respectively. A venous blood sample was analyzed for Thyroid Stimulating Hormone (TSH), free triidothyronine (fT3), and free tetraiodothyronine (fT4). This data was analyzed to determine frequencies and associations.
Results: Seventy-six patients were recruited into the study. Sixty-one participants were female. The mean TSH level was 5.8Miu/L. The frequency of thyroid dysfunction was 47.4%. Overt hypothyroidism was the most common form of thyroid dysfunction at 39.5% while 6.6% had Sick Euthyroid. Majority of the participants, 75%, had low disease activity, mean CDAI was 11.6. Forty-one (53.9%) participants had no disability, mean HAQ was 0.5. Correlations between thyroid dysfunction and advancing age, duration of disease, level of disease activity, and functional disability did not attain statistical significance.
Conclusion: Thyroid dysfunction is common among patients with RA with no significant association found between thyroid dysfunction socio-demographic characteristics, clinical characteristics, level of disease activity, and functional status.

Key words: Thyroid dysfunction, Rheumatoid arthritis, Disease activity, Functional disability