Relationship of Neuropathic Symptoms to Overall Pain and Activity in ESKD

Background: End stage kidney disease (ESKD) is associated with decreased functional status, frailty and poor quality of life. Peripheral neuropathy is noted to increase the occurrence of these outcomes in clinical practice. Uremic neuropathy is a progressive sensorimotor axonal neuropathy with 70-100% of patients endorsing symptoms, oftentimes treated with medications. Data regarding quantification of nerve related symptoms in ESKD, its effects on pain perception, physical activity, and functioning are not well characterized. This study examines these relationships. Methods: Subjects with ESKD completed 3 separate surveys within 2 weeks of enrollment, the brief pain inventory (BPI) to assess severity of pain and its effect on daily function, the neuropathic pain questionnaire (NPQ) to identify neuropathic pain and the Physical Activity in the Elderly (PASE) questionnaire to assess physical activity. Demographics, comorbidities, dialysis prescription, laboratory values and medications were collected. Pearson’s correlation was used to test relationships between survey scores. Multivariable regression was used to identify characteristics that are predictive of poor pain severity (PS) and pain interference (PI) scores, PASE scores as well as the NPQ score. SPSS 29.0 was used for all analyses. Results: Twenty-eight participants were enrolled. Median age was 60 (IQR 48-67.5) years with 75% black and 50% male participants. Hypertension and diabetes (DM) were present in 85.7% and 46.4% respectively. The most reported sites of pain on BPI were feet, back, and knees. The NPQ identified 10 participants as having neuropathic pain. Median PASE score was 74 (IQR 25-130), PS score of 3.4 (IQR 1.5-5.1) and PI score 3.9 (IQR 0.5-7.1). The PS and PI scores showed significant correlation (p = 0.002). The NPQ score was significantly associated with PS (p =0.046) and PI scores (p = 0.024) when adjusting for demographics and DM status. PI scores were inversely associated with serum calcium (p = 0.023) and sodium (p = 0.027) levels. PASE scores were associated with age but not with BPI or NPQ scores. Conclusion: Participants with neuropathic pain reported higher PS and PI scores. PASE scores are extremely low in ESKD and are not significantly impacted by pain characteristics. Impact of low sodium and calcium levels on pain perception is consistent with prior studies.