Calcium,Parathyroid Hormone,and Vitamin D: Major Determinants of Chronic Pain in Hemodialysis Patients

Background and objectives: Pain is a frequent complaint of hemodialysis (HD) patients, yet information regarding its causes and frequency is relatively scarce. The aim of this study was to evaluate the frequency and possible causes of chronic pain in patients who are on long-term HD.Design, setting, participants, & measurements: We prospectively enrolled 100 patients who were undergoing maintenance HD for at least 3 mo. Pain was evaluated using the Brief Pain Inventory. Data collected on each participant included age, gender, ethnic origin, body mass index, smoking habits, time on dialysis, type of blood access, comorbidities, and biochemical and hematologic parameters.Results: The average age was 64.5 yr; the average time on dialysis 40.4 mo. Forty-five patients were male. Thirty-one participants were of Arabic origin. Fifty-three patients had diabetes, 36 of whom had diabetic retinopathy. Although 51 patients experienced chronic pain, only 19.6% described the pain as severe. Musculoskeletal pain, neuropathic pain, and headache were the most prevalent forms of pain. The presence of diabetic retinopathy and neuropathy (but not diabetes per se) and levels of intact parathyroid hormone, calcium, and calcitriol (but not 25-hydroxyvitamin D₃) differed significantly between those who experienced chronic pain and those who did not. On a logistic regression model, higher serum calcium levels and intact parathyroid hormone levels >250 pg/ml were independently associated with chronic pain, as well as the presence of diabetic retinopathy. Calcitriol had a marginal effect.Conclusions: Disturbed mineral metabolism is strongly associated with chronic pain in long-term HD patients, along with microangiopathy.Pain is a frequent complaint of hemodialysis (HD) patients (1–3), yet information regarding its origins, frequency, and management is relatively scarce. Most published data come indirectly from studies focusing on health-related quality of life (1,3). The reported frequency of pain varies widely in these patients. Murtagh et al. (4), in a review of symptoms in ESRD, reported a weighted mean pain prevalence of 47%, with a range of 8 to 82%.Although well-accepted guidelines are available for the management of cancer-related pain (5), no such recommendations exist for pain associated with HD. One review (6) suggested using the same step-wise approach promulgated by the World Health Organization to treat cancer pain; however, the treatment of HD patients is complicated by the need to adjust frequently the dosage of analgesic drugs and by increased risk for adverse effects (7,8). It is of no surprise, therefore, that an article from the Dialysis Outcomes and Practice Patterns Study (DOPPS) by Bailie et al. (9) reported an undertreatment of pain in HD patients. In fact, pain was not treated adequately in the majority of patients. The purpose of this study was to evaluate the frequency and possible associations of chronic pain in patients who are on long-term HD.