High prevalence of diffuse idiopathic skeletal hyperostosis (DISH) among obese young patients - A retrospective observational study.

Objective: Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by ossification of ligaments and entheses, and most commonly affects the spinal column. The prevalence of DISH is increasing with age and is considered uncommon before the age of 50 years, with an estimated prevalence of less than 5 %. DISH is known to be highly associated with metabolic syndrome and obesity. We aim to assess the prevalence of DISH among young (≤50 yr.) patients suffering from severe obesity (BMI of 35 kg/m or higher).

Methods: A retrospective analysis assessing chest and spine radiographs (including Computed Tomography, CT) of patients with BMI≥35 visiting the bariatric ambulatory clinic in an academic medical center from 2013 to 2022. Patients included in the analysis were 31-50 years old. Diagnosis of DISH was made according to the Resnick criteria. The prevalence of DISH was calculated. Demographic, clinical and laboratory data were collected and compared between the DISH and non-DISH groups.

Results: 183 young (mean age: 40.4; 118 females, 64.2 %) obese (BMI median: 40.6; range 35-73) patients were included in the radiographic review. DISH was diagnosed in 33 patients (18.0 %; 95 % CI: 13.1-24.2 %) which was significantly higher than the expected 10 % (Z = 3.62, p<.001); another 8 patients (4.4 %; 95 % CI: 2.2-8.4 %) were considered as "near DISH" (not fulfilling yet the Resnick criteria) as it represents a pre-disease state. Patients diagnosed with DISH were significantly older than patients without DISH (t = 4.54, p<.001), as the prevalence of DISH increased by age (linear association=14.95, p<.001). There was a statistically significantly higher prevalence of hypertension (χ2 = 8.30, p<.004), smoking (χ2 = 4.69, p<.03) and OSA (χ2 = 6.16, p<.013) in the DISH group as compared to their non-DISH counterparts.

Conclusion: The prevalence of DISH among obese young patients was 18 %, which is much higher than in the general population. Early-onset DISH should be regarded as a musculoskeletal obesity-related complication.