Background   Psoriatic patients have a higher risk of low bone mineral density and fracture than normal people, causing huge economic burden to patients' families and society. Therefore, early and accurate identification of high-risk patients is of great significance for early prevention and treatment.

  Objective   To analyze the associated factors of low bone mineral density in patients with plaque psoriasis, and build a risk prediction model of low bone mineral density for plaque psoriasis.

  Methods   From January 2021 to March 2022, clinical data about 80 plaque psoriasis patients and 60 non-psoriasis patients with similar age and gender admitted to the Dermatology Department of the First Medical Center of Chinese PLA General Hospital were recorded and analyzed. Based on univariate and multivariate logistic regression, the associated factors of low bone mineral density in patients with plaque psoriasis were analyzed, and the prediction model was constructed. Finally, the predictive performance of the model was evaluated by the receiver operating characteristic curve (ROC) and calculating the area under the curve (AUC).

  Results   Of the 80 patients in the plaque psoriasis group, there were 57 males and 23 females, with an average age of 46.29 ± 15.78 years. Of the 60 patients in the non-psoriasis group, there were 41 males and 19 females, with an average age of 50.82 ± 17.39 years. No statistically significant differences between the two groups were found (P > 0.05). However, the BMD of lumbar spine and hip joint in the plaque psoriasis were significantly lower than those in the non-psoriasis group (-1.27 ± 1.11 vs -0.72 ± 1.40, -0.92 ± 0.82 vs -0.62 ± 0.81, P < 0.05, respectively). Univariate logistic regression analysis showed that age, BMI and PASI scores were related to the occurrence of low bone mineral density in patients with plaque psoriasis (P < 0.05). Multivariate logistic regression analysis showed that age (OR: 1.040; 95%CI: 1.004 - 1.078), PASI score (OR: 1.111; 95%CI: 1.004 - 1.229) and BMI (OR: 0.808; 95%CI: 0.697 - 0.938) were independently associated with the decrease of bone mineral density in plaque psoriasis. A prediction model was constructed according to the regression coefficient of each variable, and the ROC curve was drawn, the AUC value was 0.772 (95%CI: 0.667 - 0.877). When the optimal cut-off of the prediction model was 0.697, the sensitivity was 62.7% and specificity was 82.8%.

  Conclusion   The bone mineral density of lumbar spine and hip joint in patients with plaque psoriasis are significantly lower than the other patients. The prediction model based on logistic regression analysis has high sensitivity and specificity for predicting whether plaque psoriasis patients have low bone mineral density. Targeted preventive measures can be taken according to this model to reduce the incidence of low bone mineral density, osteoporosis and even fracture.