Table 4: Pearson’s correlation coefficients between BMI and the outcome measures before surgery, at 6 months and 1 year after surgery and between BMI and the change scores.

OKSSF12 (PCS)SF12 (MCS)

Pre-op.0.271*−0.086−0.101
6 months0.1150.143−0.139
1 year0.072−0.206−0.041
Pre-6m−0.082−0.117−0.015
Pre-1yr−0.194−0.159−0.068

* P < 0.01, PCS: physical component summary of the SF12, and MCS: mental component summary of SF12.