Course of back pain across 5 years: a retrospective cohort study in the general population of Switzerland.

STUDY DESIGN: A retrospective cohort study in the general population of Switzerland. OBJECTIVE: To investigate the course of back pain (BP) across 5 years and the impact of BP history on its incidence and recurrence. SUMMARY OF BACKGROUND DATA: Longitudinal studies on BP performed in the general population have reported varying prevalence and incidence rates. Most studies compared two points in time with varying time periods. This study adds information about the course of BP exploring five points in time with annual intervals. METHODS: The Swiss Household Panel is a representative population-based cohort study (N = 7799). The question analyzed in the present study asked about "bad back or lower back problems at least once a month in the last 12 months (BP)." Among 7791 persons who answered this question during the baseline survey in 1999, 3881 persons (49.8%) completed all annual follow-up surveys through 2003 and represent the study sample. In each year, the 1-year prevalence, incidence, and recurrence of BP were calculated. The course of BP was analyzed according to the number of years with BP, the constancy of BP status, and the trend of BP. For each analysis, the observed frequency was compared with expected frequencies on the basis of two theoretical models. RESULTS: In the study sample (age 44.0 ± 15.6 years, 57.7% women), BP prevalence was 33.2% at baseline. In the follow-up surveys, mean prevalence was 37.7%, mean incidence 19.6%, and mean recurrence 69.0%. The most frequently observed courses across 5 years were those with a constant status: BP always absent (n = 1346, 34.7%) or BP always present (n = 538, 13.9%). BP recurrences increased with increasing numbers of previous consecutive years with BP from 46.9% (1 year of previous BP) to 88.1% (at least 4 years of previous BP). CONCLUSION: BP history is highly predictive for future BP episodes.

Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review.

OBJECTIVE: To summarise the evidence on accuracy of the Ottawa ankle rules, a decision aid for excluding fractures of the ankle and mid-foot. DESIGN: Systematic review. DATA SOURCES: Electronic databases, reference lists of included studies, and experts. REVIEW METHODS: Data were extracted on the study population, the type of Ottawa ankle rules used, and methods. Sensitivities, but not specificities, were pooled using the bootstrap after inspection of the receiver operating characteristics plot. Negative likelihood ratios were pooled for several subgroups, correcting for four main methodological threats to validity. RESULTS: 32 studies met the inclusion criteria and 27 studies reporting on 15 581 patients were used for meta-analysis. The pooled negative likelihood ratios for the ankle and mid-foot were 0.08 (95% confidence interval 0.03 to 0.18) and 0.08 (0.03 to 0.20), respectively. The pooled negative likelihood ratio for both regions in children was 0.07 (0.03 to 0.18). Applying these ratios to a 15% prevalence of fracture gave a less than 1.4% probability of actual fracture in these subgroups. CONCLUSIONS: Evidence supports the Ottawa ankle rules as an accurate instrument for excluding fractures of the ankle and mid-foot. The instrument has a sensitivity of almost 100% and a modest specificity, and its use should reduce the number of unnecessary radiographs by 30-40%.