Cumulative probability of osteoarthritis progression according to mitochondrial DNA (mtDNA) haplogroups and results of the extended Cox proportional hazard model.

KL: Kellgren and Lawrence; JSN: joint space narrowing; BMI: body mass index; bl: baseline; (¥): cumulative osteoarthritis progression rate after 48 months of follow-up; HR: hazard ratio; CI: confidence interval; (#): confidence intervals for the hazard ratios obtained using the bootstrap methodology by the percentile method; (±): the worst knee at baseline refers to the radiological status of the knee attending to (highest) KL grade, JSN grade, osteophytes grade or sclerosis grade, as appropriate on each case; (*): statistical significance declared at p≤0.05. Cumulative probability of osteoarthritis progression according to mitochondrial DNA (mtDNA) haplogroups and results of the extended Cox proportional hazard model.