Higher incidence of common diagnoses in patients with low back pain in primary care.

Most studies on comorbidity in low back pain (LBP) have been conducted in specialized settings with the use of self-reports. This study has an original design using data from family practices: the incidence of the most frequent diseases was compared in patients with and without LBP in 2004. The database includes data from 67 family physicians in 52 family practices in Flanders, Belgium. It contains data from 160,000 different patients with 1,500,000 diagnoses during the period 1994 to 2004. The incidence of the most frequent diagnoses is presented in patients with and without LBP in 2004. The diagnoses were coded according to the ICPC-2-classification. In 2004, the incidence of LBP was 51.4‰ (95% CI: 49.8 to 53.1) in patients aged 18 or older. The incidence was slightly higher in women than in men: 53.0‰ (95% CI: 50.7 to 55.4) vs. 49.9‰ (95% CI: 47.7 to 52.3). The highest incidence was recorded in the age group of 50 to 54 years. The most frequent "other" diagnoses in patients with and without LBP are comparable, but some were more frequent in patients with LBP. Respiratory infections and diseases of the locomotor apparatus (neck syndrome, bursitis) are more frequent in patients with LBP. Low back pain is one of the most frequent diagnoses in general practice. Striking is the relatively higher frequency of common self-limiting diseases in patients with a diagnosis of LBP during the same year. To the authors' knowledge, this is the first time that medical demands for non-LBP reasons in family practice have been reported in patients with LBP.