[An evaluation of pain in haemodialysis patients using different validated measurement scales].

Pain in haemodialysis is very common, although frequently underdiagnosed. Chronic pain in dialysis has been scarcely evaluated, and intradialytic pain has not been specifically analyzed. Our aim was to compare intradialytic versus chronic pain characteristics in the same group of twenty-seven hemodialyzed patients, to investigate whether there were or not differences between them. Several validated scales were used: a) Analogical Visual Scale, defines pain intensity from 0, no pain, to 10, the worst pain; b) Pain Management Index, that results from subtracting pain level from analgesic use, ranging from - 3 (inadequate) to + 3 (adequate management); c) McGill Pain Questionnaire, which defines three items: pain related qualitative index, number of words chosen, and present pain intensity; and d) Brief Pain Inventory, which analyses influence of pain in patient's life, was only aplicable to evaluate chronic pain. Tests were administered firstly during the dialysis session for evaluating intradialytic pain, and another day out of the session to evaluate chronic pain. Ischemic pain was the most common during the session (37%), whereas muscle-skeletal was more frequent out of the session (77%). Prevalence of pain was higher during the session (92.5% vs 77.7%, p < 0.05). Number of weekly sessions with pain was 1.78 +/- 1.2. Analogical visual score was slightly higher during the session with respect to chronic pain (3.28 +/- 2.22 vs 2.67 +/- 2.13, p = NS). Pain Management Index scores were significantly different (intradialytic: -0.81 +/- 0.76, chronic pain: -0.12 +/- 0.94). McGill test scores were similar in both situations. Only in chronic pain, time on dialysis correlated significantly with analogical visual scores, pain related index and number of words chosen, and parathyroid hormone levels with analogical visual scores and interference to displacement score from Brief Pain Inventory. Farmacological treatment was prescribed in 11% of patients with intradialytic pain (63.1% of responders) compared to 74% for those with chronic pain (53.1% of responders). In conclusion, pain in hemodialysis is very frequent and becomes undertreated. Pain scales used have been shown to be useful in this setting. Several differences appear between intradialytic and chronic pain. Chronic pain is less frequent and intense, better treated, mainly derived from a muscle-skeletal source, and it is related to time on dialysis and to secondary hyperparathyroidism.