Association of renal failure with thyroid dysfunction: A retrospective cohort study

Chronic renal failure is often associated with multiple organ co-morbidities, including thyroid dysfunction. This has been associated with poorer prognosis, particularly in patients with end-stage renal disease. This study aimed to examine the relationship between renal failure and thyroid dysfunction in an outpatient setting at the King Abdulaziz University Hospital, Saudi Arabia, from January 2011 to June 2012. Demographic and biochemical data were extracted from medical records. Differences in the levels of thyroid hormones and lipids between the four renal function groups were analyzed using the chi-square test for categorical variables and Kruskal- Wallis test for binomial variables. A total of 486 patients were included in the study population, of whom approximately half were female, and the median (range) age was 61 (17-90) years. According to creatinine measurements, renal function was normal in 48 participants, 290 had mild renal failure, 122 had moderate renal failure and 26 had severe renal failure. No significant relationships were observed between renal failure and cardiac or pulmonary dysfunction. Free triiodothyronine (FT3) levels were significantly reduced (P = 0.005) and both free thyroxin (FT4; P = 0.034) and parathyroid hormone (PTH; P = 0.028) significantly increased with increasing severity of renal failure. Patients with moderate to severe renal failure displayed reduced hemoglobin levels and were significantly more likely to be anemic (P <0.001). Highly significant increases in alkaline phosphatase (P <0.001), uric acid (P <0.001) and low-density lipoprotein-cholesterol (P = 0.014) levels were also observed with increasing renal dysfunction. To conclude, it was observed that renal dysfunction is associated with notable changes to other organ systems, including the thyroid. Further studies may investigate the association of multiple organ co-morbidities with prognosis in patients with chronic renal failure.