Glucose Homeostasis Influences the Risk of Incident Knee Osteoarthritis: Data From the Osteoarthritis Initiative

We aimed to determine if serum measures of impaired glucose homeostasis (glucose concentrations or glycated serum protein, GSP) or systemic inflammation (high-sensitivity C-reactive protein, CRP) are related to incident typical knee osteoarthritis (KOA) or incident accelerated KOA. We conducted a case-control study using the Osteoarthritis Initiative's baseline and first four annual visits. All participants had no radiographic KOA at baseline (Kellgren-Lawrence [KL]<2). We classified three groups: (i) incident accelerated KOA: >1 knee developed advance-stage KOA (KL Grade 3 or 4) within 48 months; (ii) incident typical KOA:>(-)1 knee increased in radiographic scoring within 48 months (excluding those with accelerated KOA); and (iii) No KOA: no change in KL grade by 48 months. We matched on sex. A laboratory blinded to group assignment used baseline serum samples to conduct assays for CRP, GSP, and glucose. Due to nonlinear relationships, we used three piece-wise multinomial logistic regression models to determine if baseline CRP, GSP, or glucose were associated with incident typical KOA or accelerated KOA compared with no KOA. We adjusted for age, body mass index, and sex. We analyzed 54 adults/group. Lower and higher GSP concentrations were associated with incident typical KOA compared with adults with concentrations (log) closer to 5.7 (lnGSp<5.7: OR = 0.28, 95% CI = .08-0.93; lnGSp>5.7: OR = 3.21, 95% CI = 1.07-9.62). Glucose, GSP, and CRP were not significantly associated with incident accelerated KOA. Glucose homeostasis may predict individuals at risk of incident typical KOA but not accelerated KOA, which may indicate accelerated KOA is a distinct disorder from typical KOA. (C) 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.