To examine in more detail the association between KCNJ6 SNPs and rescue analgesic requirements, a haplotype-based test was performed. As shown in Table 6A, a significant association was found between the −1250G/1032A haplotype and the increased frequency of rescue analgesic administration in all patient subjects (R2 = 0.120, adjusted P = 0.015). Although no significant associations were observed between each of the KCNJ6 haplotypes and total dose of rescue analgesics administered in all patient subjects and male subjects (R2 = 0.080, P = 0.328; R2 = 0.028, P = 0.765, respectively), the −1250G/1032A haplotype was significantly associated with total dose of rescue analgesics administered in female subjects (R2 = 0.277, adjusted P = 0.038; Table 6B). Associations between each of the G-1250A/A1032G haplotypes and NRS pain scores were not significant (data not shown).
