# Incidence of skin and soft tissue infections in general practice and out-of-hours services in Norway 2006–2022

## TL;DR

This study analyzed the incidence of skin and soft tissue infections in Norwegian primary care from 2006 to 2022, finding a general decline except in elderly and multimorbid patients.

## Contribution

The study provides updated epidemiological data on SSTI incidence in primary care in Norway over 16 years.

## Key findings

- The overall annual incidence of SSTIs decreased from 23.7 to 17.0 per 1000 inhabitants between 2006 and 2022.
- Elderly patients and those with multimorbidity had higher and increasing SSTI incidence rates.
- Impetigo, infected wounds, and cellulitis showed the largest declines in incidence.

## Abstract

Most patients with skin and soft tissue infections (SSTIs) are treated in the primary care setting. However, recent epidemiologic data in primary care are limited.

To investigate incidence and patient characteristics of SSTI episodes in daytime general practice (DGP) and out-of-hours (OOH) services in Norway.

Registry-based study using reimbursement claims data from Norwegian primary care for the period 2006–2022. SSTI consultations were grouped into episodes, and patient morbidities were identified using a morbidity index. Incidence rates were calculated based on population data from Statistics Norway.

During the study period, 1 171 018 unique patients experienced altogether 1 727 736 SSTI episodes in Norwegian primary care. Most SSTI episodes (76.1%) were managed in DGP and incidence rates peaked in the third quarter. The overall annual incidence was 20.0/1000 inhabitants, with a decrease from 23.7/1000 inhabitants in 2006 to 17.0 in 2022. During the period, the largest decline among the SSTIs was observed for impetigo (68.1% decrease), infected wound or bite (46.0% decrease), and cellulitis and erysipelas (23.6% decrease), while abscess and furuncle and paronychia all remained stable. Overall, elderly patients and patients with a morbidity score of one or more had higher incidence rates of SSTIs, that increased over the period.

The incidence of SSTIs in DGP and OOH services in Norway declined over the study period, except for elderly and persons with multimorbidity. As the population is increasingly older and multimorbid, such infections may represent a growing challenge in the future.