European Radiology: Relationship between diabetes-related thigh muscle degeneration and knee osteoarthritis

Due to the associated high mortality and morbidity, diabetes mellitus (DM) is one of the
most important public health challenges.
Studies have shown that DM affects the mass and strength
of skeletal muscle.
Regardless of BMI, waist circumference, or the amount of visceral adipose tissue, DM patients have increased fat deposits between abdominal skeletal muscle (intermuscular adipose tissue or MAT) and inside (within MAT).

DM-related muscle degeneration is clinically important in the context of concomitant knee osteoarthritis (KOA), where thigh muscle degeneration is an independent risk factor
for KO exacerbation.

Multiple studies have shown that KOA and DM often coexist
.
Some studies have shown that DM is associated with
the progression of symptomatic KOEA in patients who have established KOA.
However, at this stage, the exact mechanism by which DM may lead to KOA exacerbations remains unclear
.

Recently, a study published in the journal European Radiology evaluated the correlation between longitudinal degeneration of thigh muscles and DM, DM and KOA structure and clinical prognosis, which provided a reference for further clarifying the pathophysiological process of DM and KOA and providing a reference for further treatment
.

Participants from the Osteoarthritis Initiative (OAI) were included in this study, and each patient had an imaging KOA (Kellgren-Lawrence grade ≥2).

Using propensity score (PS) matching, the thighs and corresponding knee joints of KOA patients with and without DM were matched to identify potential confounding factors
.
In this study, a proven deep learning method was developed and used for longitudinal segmentation
of the thigh.
The relationship between DM and 4-year longitudinal muscle degeneration of biological markers such as muscle cross-sectional area (CSA) and percentage contraction (non-fat CSA/total CSA) was also evaluated.

This study further investigated the relationship between DM and the 9-year risk of radiographic progression of KOA, knee replacement (KR), and worsening of symptoms.

After PS matching, a total of 698 thigh/knee patients (185:513 with: without DM; Average ±SD age: 64±8-years; Female/male: 1.
4).

Baseline DM was associated with a decrease in percentage contraction of the total thigh muscle and quadriceps muscles (mean difference, 95% CI -0.
16%/year, -0.
25 to -0.
07, and -0.
21%/year, -0.
33 to -0.
08).

DM was also associated with an increased risk of worsening of KOA-related symptoms (hazard ratio, 95% CI 1.
70, 1.
18-2.
46), but not
radiographic progression or KR.
The decrease in quadriceps contraction partially mediates the increased
risk of worsening symptoms in patients with DM.

The mediating role of MRI biomarkers of table thigh muscles in the incidence of DM and KOA symptomatic states

The results of this study showed that DM was associated with
muscle degeneration and worsening of symptoms in patients with KOA.
Muscle degeneration associated with DM often manifests as a decrease in quadriceps contractility, partially mediating worsening of KOA symptoms
.
Further clarification of the mechanisms and definitions of the optimal clinical treatment strategy paves the way for minimizing the impact of DM on the worsening of
KOA-related symptoms.

Original source:

Bahram Mohajer,Kamyar Moradi,Ali Guermazi,et al.
Diabetes-associated thigh muscle degeneration mediates knee osteoarthritis-related outcomes: results from a longitudinal cohort study.
DOI:10.
1007/s00330-022-09035-4