OBJECTIVE: The objective of this study was to investigate the association between pain response and health-related quality of life (HRQoL) in patients with diabetic peripheral neuropathic pain (DPNP).
METHODS: EQ-5D data was collected at baseline and endpoint in three large placebo controlled randomised trials which evaluated duloxetine treatment for DPNP over a 12- week horizon. Patients had a clinical diagnosis of pain due to bilateral peripheral neuropathy caused by diabetes, had a mean 24-hour average pain severity score ≥ 4 on the 11 point Likert scale (“0 = no pain” and “10 = pain as bad as you can imagine”) and suffered from daily pain for at least 6 months. Treatment response was based on the level of change observed in the average pain severity score. Three levels of clinically meaningful pain response were defined: full response (≥50% change in average pain severity), partial response (30 to 49% change average pain severity), and no response (<30% change in average pain severity). Utility data at the trial endpoint were pooled and stratified into the corresponding pain response thresholds.
RESULTS: Patients had pain and utility scores measured at baseline (n = 1139) and trial endpoints (n = 998) across the three randomised trials. The average pain score at baseline was 5.8 ± 1.5 with a corresponding utility score of 0.58 ± 0.26. At trial endpoint, patients in the no response to treatment category had lower utility scores (0.61 ± 0.24) compared to patients with either a partial response (0.70 ± 0.16) or full response (0.78 ± 0.16). In addition, a statistically significant negative correlation was found, indicating that increasing pain severity was strongly associated with lower HRQoL in DPNP patients.
CONCLUSION: Pain response had a considerable impact on HRQoL in DPNP patients. In addition, pain severity scores were significantly associated with lower HRQoL.
