Alarming increase in the registration of degenerative rotator cuff-related lesions a nationwide epidemiological study investigating 244,519 patients.

PURPOSE AND HYPOTHESIS: Shoulder lesions are common and a challenge to diagnose. They often result in significant disability for the patient and are an economic burden to society. From recent studies, an increasing incidence has been reported. The purpose of this study was to investigate and map the incidence of shoulder lesions in Denmark from 1996 to 2013 with focus on sex, age and geographical area.

METHODS: The Danish National Patient Registry was searched retrospectively to find the number of shoulder lesions in Denmark during the period 1996-2013. Regional population data were retrieved from the services of Statistics Denmark. Incidence rates were analysed using Poisson regression models, and all analyses were done in R 3.2.2, and p values less than 0.05 were considered statistically significant.

RESULTS: During the 18-year period, 244,519 patients with a DM 75 diagnosis were registered. Male-to-female ratio was 51:49, and median age was 51. Most frequent were rotator cuff syndrome with a mean incidence rate of 313.3 (confidence interval 241.8-384.8) per 105 person-years at risk (PYRS). A statistically significant increase in overall incidence rate from 149.4 per 105 PYRS in 1996 to 715.3 per 105 PYRS in 2013 was found (p < 0.01). Incidence was highest for men aged 51-70 (1085.1 per 105 PYRS in 2013). There was no significant difference in incidence between sexes. Rural areas had a 1.4-fold higher mean incidence rate than urban areas.

CONCLUSION: The incidence of shoulder lesions rapidly increased mainly due to an increase among people of working age (31-70 years). There were no significant differences in incidence between sexes. Rural areas had a 1.4-fold higher incidence rate than urban areas. As shoulder lesions impose a huge socioeconomic burden on society, not to mention a great distress to the patient, the present findings is highly relevant for political decision-making regarding preventive and health promoting initiatives.