Comorbidity with type 2 diabetes may intensify joint pain in patients with osteoarthritis

Pain severity at any localized osteoarthritis (OA) site appears to be greater for patients with comorbid type 2 diabetes (T2D), as shown in a recent study.

“T2D as a systemic disease results in chronic hyperglycaemia, which is associated with increased production of oxidative stress and inflammatory cytokines at any joint, and these mechanisms could elucidate the association between T2D and pain severity in this population,” according to the investigators.

The analysis included 819 patients (mean age, 65.08 years; 54.3 percent female) with localized OA, among whom 148 had comorbid T2D. Patients with vs without the comorbidity were older and had higher body mass index (BMI) and pain severity.

In multiple linear regression models, T2D showed a strong association with heightened severity of pain (B, 1.07, 95 percent confidence interval [CI], 0.25–1.88; p=0.014) at any localized OA site, including weight- and nonweight-bearing joints (ie, knee, hand and shoulder) but not the hip and the ankle. [Pain Med 2019;doi:10.1093/pm/pnz299]

In the subgroup of diabetic OA patients with available data for HbA1c (n=87), elevated HbA1c values also emerged as a significant risk factor for higher pain severity (B, 0.36, 95 percent CI, 0.036–0.67; p=0.029).

Medication adherence should therefore be enforced in order to improve HbA1c control and reduce the level of pain in the present population, the investigators pointed out.

“As increased HbA1c was associated with increased pain severity only after controlling for specific medications including pain meds, antihypertensive, antilipemic, insulin and hypoglycaemic, these factors might become potential targets for managing pain in people with localized OA and T2D,” they added.

The present data are in line with reports from previous studies examining the association between diabetes and pain severity in patients with knee or hand OA. [Pain 2017;158:1743-1753; Curr Rheumatol Rev 2015;11:8-14; Arthritis Care Res 2015;67:187-195; J Clin Endocrinol Metabol 2014;99:3177-3183]

But unlike the previous investigations, the current study examined localized OA affecting one or two joints, in any possible joint such as the knee, hip, ankle, hand or shoulder, the investigators said. As such, the present data “may give clinicians and researchers a holistic picture of the burden of T2D on localized OA symptoms for possible joints that can be affected by OA.”

However, they advised cautious interpretation of the findings regarding the association of T2D with shoulder OA pain, as the relationship between T2D and other painful shoulder disorders is not specific to OA.

“Future research should examine in depth the association between T2D and other shoulder disorders,” they said.