Reliability among clinicians diagnosing low back-related leg pain.

Purpose: To investigate agreement and reliability among clinicians when diagnosing low back-related leg pain (LBLP) in primary care consulters.
Methods: Thirty-six patients were assessed by one of six physiotherapists and diagnosed as having either leg pain due to nerve root involvement (sciatica) or referred leg pain. Assessments were video recorded. In part one, the physiotherapists each viewed videos of six patients they had not assessed. In part two, videos were viewed by another six health professionals. All clinicians made an independent differential diagnosis and rated their confidence with diagnosis (range 50-100 %).
Results: In part one agreement was 72 % with fair inter-rater reliability (K = 0.35, 95 % CI 0.07, 0.63). Results for part two were almost identical (K = 0.34, 95 % CI 0.02, 0.69). Agreement and reliability indices improved as diagnostic confidence increased.
Conclusion: Reliability was fair among clinicians from different backgrounds when diagnosing LBLP but improved substantially with high confidence in clinical diagnosis.