Frequency, combinations and clinical relevance of outpatient low back pain diagnoses: analysis of claims data in a population-based cohort study.

backgroundClaims data are often used to investigate the quality of care for patients with low back pain (LBP). However, there is no standard regarding the preferred choice of ICD-10 codes for identifying patients with LBP, and guidelines for the treatment of LBP differ in their interpretation of ICD-10 codes. Furthermore, for some indicators measuring the quality of care, such as the appropriate use of imaging, it is necessary to differentiate between cases with specific, treatable causes and those without. This study therefore investigates coding practices for LBP in outpatient care and the use of imaging across specialist groups over a six-year period.

methodsBased on the TREND cohort of the population-based Study of Health in Pomerania (SHIP), coding practices in claims data were analysed using data from 3,837 statutorily insured participants for the years 2014-2019. In total, eleven ICD-10 categories of relevance to LBP were included. We evaluated the findings based on two German guidelines: one for specific and one for non-specific LBP.

resultsAt least one LBP diagnosis was coded for 2,474 participants (64%) during the entire observation period. The predominant ICD-10 category was M54 (dorsalgia, 87% of patients with LBP). Around half of the participants with M54 diagnoses also had diagnoses from other LBP-related categories in the same year. Diagnoses that can be assigned to specific LBP according to the respective German guideline occurred in 86% of patients with LBP. Participants who consulted only general practitioners during the observation period were more likely to receive only an M54 diagnosis and less likely to undergo imaging procedures.

conclusionsThe results underline the high epidemiologic relevance of LBP. Using the German guideline on specific LBP as a reference, we categorized most LBP diagnoses as specific, contrary to common international assumptions. Most patients with LBP received multiple ICD-10 codes, complicating the distinction between non-specific and specific LBP based on claims data. Health care analyses on LBP require transparent reporting of the ICD codes used, along with a detailed discussion of the data's limitations.