Factors affecting lumbar surgery outcome: A nation-wide, population-based retrospective study

Lower back pain is a very common symptom and treatment strategies vary according the severity and duration of illness. Surgical approaches are becoming increasingly popular with the advent of new and less invasive technologies; however, treatment outcomes are not yet well established on a population-based level. Taiwan's National Health Insurance Research Database (NHIRD) is longitudinal and includes 98% of the population since its inception in 1995. The database includes the ICD 9.0 codes (International Classification of Diseases) of all patients with lower back pain and lumbar surgery; furthermore, all the prescriptions.

As part of a population-based cohort study of one million participants randomly selected from the NHIRD, we analyzed changes in prescription of analgesics 1 year before and 1 year after lumbar surgery; comorbidities, such as diabetes, asthma, osteoporosis, arthritis, depression and anxiety were also analyzed as covariates. A total of 3916 cases were enrolled in final analysis.

Post-operatively, the defined daily dosage (DDD) of analgesics decreased from a median DDD of 50.0 to a median of 14.2. In a multivariate model analysis, female, older age, anxiety and asthma were the significant factors for unfavorable outcome (defined by dosage of analgesics decreased less than 50% after surgery).

The analgesics significantly decreased for patients received lumbar surgeries, implying the decreased of pain. In addition, co-morbidity factors were identified by the failure for analgesics reduction, such as female, older age, anxiety and asthma. For patients with lower back pain, these factors should be considered before receiving lumbar surgeries.