Pain is an important cause of disability and poor quality of life in chronic and acute diseases. Nevertheless, pain and its consequences often remain under-recognized. The World Health Organization (WHO) produced guidelines for the management of pain, but they do not include clear indications for patients affected by chronic kidney disease (CKD). In CKD patients, pain can have a multi-factorial origin: it can be caused by comorbidities, CKD complications, and in dialysis patients by the dialysis procedure itself.
In clinical practice, pain management in CKD patients may be problematic because of difficulties in handling analgesic drugs, as renal failure modifies drug pharmacokinetic and pharmacodynamic profiles. Therefore, there is a strong need to improve knowledge on pain management, quantifying its entity and producing informative material to help patients and healthcare professionals to better face this important issue. In this perspective, the aim of the present study is to evaluate prevalence and characteristics of chronic pain in CKD stage 5D patients.
A CKD specific questionnaire was created adapting the Italian version of “McGill Pain Questionnaire”. First, it was submitted to patients during the hemodialysis session. Patients could ask for help to nurses if they were not able to independently complete the questionnaire. They were asked to report pain felt during that dialysis session. Intensity of pain was reported in a numerical rating scale (NRS), from a minimum of 0 (no pain) to a maximum of 10 (worst pain). It was then asked to the patient to report on a cartoon representing the human body, the point or points where she/he feels the pain. Last, the patient had to complete three NRS at home in the interdialytic period (post-dialysis: in the evening; the day after dialysis: in the morning and in the evening), in order to highlight a possible relationship of pain with the dialysis session.
We present preliminary data from an ongoing study of 276 patients in two dialysis units. Patients had a mean age of 69.41 ± 13.17 years, duration of renal replacement therapy of 61.78 ± 72.79 months, with a higher proportion of men (68.1 vs. 31.9%). Overall, the majority of patients reported pain (Fig. 1) and about 1/10 reported very severe pain. As a function of elapsed time by dialysis, the percentage of patients with pain of moderate intensity tended to decrease while an increase (although non significant) of the percentage of patients with severe pain was found on the evening of dialysis (p=0.097, Fig.2). Pain in the lower limbs (74.2% of patients) was more frequent than in the upper limbs (37.8% of patients). However, among patients who reported pain at upper limbs we found a significant correlation with the presence of arterio-venous vascular access (p<0.05, Fig.3). Dialysis age and pain intensity were also significantly associated (p<0.001, Fig. 4). Preliminary analysis of the modified McGill questionnaire showed that In CKD stage 5D patients the quality of reported pain has a relevant affective component, compared to the sensory, nociceptive component.
Many patients (about half) report chronic pain during dialysis, with a relevant affective component. The intensity of pain is related to dialysis age. Pain in the upper limbs is related to the presence of artero-venous vascular access.