Low inter-examiner agreement of the Friedman staging system indicating limited value in patient selection

PURPOSE: The Friedman staging system is a clinical method for selecting patients with obstructive sleep apnoea who are likely to benefit from uvulopalatopharyngoplasty. The objective of this study was to evaluate the system by determining its inter-examiner agreement. METHODS: Twelve patients with obstructive sleep apnoea were examined by 14 doctors. The Friedman stage was derived from tonsil size and tongue position, and a Cohen’s kappa analysis was performed to assess inter-examiner agreement. RESULTS: One hundred and sixty-eight ratings were performed. The median kappa for tongue position was 0.32 (first and third quartiles: 0.21 and 0.44) and was 0.62 (0.50 and 0.63) for tonsil size. The median kappa for the Friedman stage was 0.38 (0.24 and 0.55), which corresponds to only a slight or fair agreement. CONCLUSION: The Friedman staging system demonstrated a low inter-examiner agreement, indicating that the system is an uncertain method for selecting patients for uvulopalatopharyngoplasty. LEVEL OF EVIDENCE: 2B.