To determine whether men with rheumatoid arthritis (RA) have abnormal hypothalamic-pituitary-gonadal axis function and to measure the effects of low dose prednisone therapy in these patients.
We measured testosterone, follicle stimulating hormone (FSH), and luteinizing hormone (LH) in 36 men aged 38-75 (mean age +/- 1 sd = 62 +/- 10 years) who had longstanding active RA (mean disease duration = 17 +/- 12 years) and in 70 healthy elderly male controls, aged 53-83 (mean age 68 = +/- 6 years). We divided the group with RA into those taking no prednisone (n = 12) and those taking 5 to 10 mg/day of prednisone (n = 24) and analyzed these groups separately to determine whether low doses of prednisone affected testosterone levels.
Compared to the healthy controls, patients with RA not taking prednisone had normal testosterone levels but significantly elevated levels of FSH and LH (p < 0.01 for both comparisons). In contrast, patients with RA taking prednisone had significantly lower testosterone levels (p < 0.05), but levels of FSH and LH were only slightly elevated compared to controls. Compared to patients not taking prednisone, patients taking prednisone had lower levels of testosterone, FSH, and LH.
Male patients with RA who are not taking prednisone have significantly elevated levels of FSH and LH with normal testosterone levels, suggesting a state of compensated partial gonadal failure. Male patients with RA taking low doses of prednisone have lower testosterone and gonadotropin levels, suggesting that prednisone may suppress the hypothalmic-pituitary-testicular axis. Since testosterone affects immune function as well as bone and muscle metabolism, androgen deficiency in some men with RA may predispose these patients to more severe disease and to increased complications of steroid therapy such as myopathy and osteoporosis.