Reliability of pressure ulcer classification and diagnosis

Aim: To assess the inter-rater reliability of the PRESSURE Trial pressure ulcer diagnosis (≥Grade 2) and skin classification for all grades between the clinical research nurse (CRN) team leader and CRNs working across different hospital sites; and CRNs and ward-based nurses. Background: The United Kingdom National Health Service Health Technology Assessment Programme has funded a multi-centre, randomized controlled trial to compare the clinical and cost-effectiveness of alternating pressure mattress overlays and mattress replacements – PRESSURE Trial. Outcome skin assessments were recorded by qualified ward-based nurses daily, and expert CRNs twice weekly. Method: Paired assessments were undertaken and skin assessed on seven body sites. The per cent agreement between nurses in the diagnosis of a pressure ulcer was determined and the Kappa statistic and confidence intervals calculated. Per cent agreement between nurses in classifying skin for all grades was also determined. Results: Assessments were undertaken by 378 pairs: 16 paired patient assessments (107 site comparisons) by the CRN team leader and CRNs, and 362 paired patient assessments (2396 site comparisons) between CRNs and ward-based nurses. There was 100% agreement between the CRN team leader and CRNs in the diagnosis of a pressure ulcer, and the Kappa statistics indicated ‘very good’ agreement. There were only two (1·9%) disagreements in classifying skin for all grades between these nurses. The agreement in the diagnosis of a pressure ulcer between CRNs and ward-based nurses varied by skin site, ranging from 93·6% to 100%, with the Kappa statistics indicating ‘good’ and ‘very good’ agreement. However, there were 508 (21·2%) disagreements in classifying skin for all grades. Conclusions: Overall agreement and Kappa statistics indicated ‘very good’ and ‘good’ agreement between expert nurses, and between expert nurses and qualified ward-based staff, respectively. However, the high prevalence of normal skin concealed clinically important disagreements in both the diagnosis of pressure ulcers and skin classification for all grades