Music therapy-induced changes in salivary cortisol level are predictive of cardiovascular mortality in patients under maintenance hemodialysis

BACKGROUND Music therapy has been applied in hemodialysis (HD) patients for relieving mental stress. Whether the stress-relieving effect by music therapy is predictive of clinical outcome in HD patients is still unclear. METHODS We recruited a convenience sample of 99 patients on maintenance HD and randomly assigned them to the experimental (n=49) or control (n=50) group. The experimental group received relaxing music therapy for 1 week, whereas the control group received no music therapy. In the experimental group, we compared cardiovascular mortality in the patients with and without cortisol changes. RESULTS The salivary cortisol level was lowered after 1 week of music therapy in the experimental group (-2.41±3.08 vs 1.66±2.11 pg/mL, P<0.05), as well as the frequency of the adverse reaction score (-3.35±5.76 vs -0.81±4.59, P<0.05), the severity of adverse reactions score (-1.93±2.73 vs 0.33±2.71, P<0.05), and hemodialysis stressor scale (HSS) score (-6.00±4.68 vs -0.877±7.08, P<0.05). The difference in salivary cortisol correlated positively with HD stress score scales (r=0.231, P<0.05), systolic blood pressure (r=0.264, P<0.05), and respiratory rates (r=0.369, P<0.05) and negatively with finger temperature (r=-0.235, P<0.05) in the total study population. The 5-year cardiovascular survival in the experimental group was higher in patients whose salivary cortisol lowered by <0.6 pg/mL than that in patients whose salivary cortisol lowered by >0.6 pg/mL (83.8% vs 63.6%, P<0.05). CONCLUSION Providing music during HD is an effective complementary therapy to relieve the frequency and severity of adverse reactions, as well as to lower salivary cortisol levels. Differences in salivary cortisol after music therapy may predict cardiovascular mortality in patients under maintenance HD.