Diagnostic accuracy and cost‐effectiveness of dermoscopy in primary care: a cluster randomized clinical trial

Abstract

Background The dermoscope improves general practitioners' (GP) sensitivity for melanoma. However, diagnostic accuracy (DA) and cost‐effectiveness of the dermoscope in primary care for the evaluation of all skin lesions suspected of malignancy remains unknown. Objectives To determine the DA and cost‐effectiveness of the dermoscope in primary care for skin lesions suspected of malignancy. Methods In a cluster randomized clinical trial, 48 Dutch general practices were randomized to either intervention group using a dermoscope or control group using only naked‐eye examination. A total of 194 lesions from 170 patients in the intervention group and 222 lesions from 211 patients in the control group were analysed for DA and cost‐effectiveness. Results The percentage of correctly diagnosed lesions in intervention group and control group was 50.5% and 40.5% respectively. This was 61.5% and 22.2% for melanomas. In the intervention group, three malignancies were treated with the expectative treatment option compared to none in the control group. The odds ratio (OR) of a correct diagnosis in the intervention group, compared to control group, was 1.51 (95% CI: 0.96–2.37) P = 0.07. Consequently, the relative risk was 1.25. The incremental cost‐effectiveness ratio was €89 (95% CI −€60 to €598), indicating that using a dermoscope costs an additional €89 for one additional correctly diagnosed patient. Additional analyses showed better effects of dermoscopy compared to the control group for 98% of the bootstrap resamples. Conclusions The probability of a correct diagnosis was 1.25 times higher using a dermoscope than without a dermoscope. Although this difference is marginally not statistically significant, dermoscopy in general practice appears to be cost effective. We therefore think that GPs should be trained to use a dermoscope, although they should realize that even with the use of a dermoscope not all lesions will be diagnosed correctly.