Validation of new items for diagnosing primary hyperhidrosis, and estimation of the prevalence of primary hyperhidrosis

Background
The Multi-Specialty Working Group on the Recognition, Diagnosis, and Treatment of Primary Focal Hyperhidrosis has developed evidence-based consensus criteria for diagnosing primary hyperhidrosis (PHH).

Objectives
To validate new questionnaire items for self-reported classification of PHH based on the consensus criteria and to estimate the prevalence of PHH.

Methods
This was a cross-sectional diagnostic accuracy study. Questionnaires containing the index tests and reference tests were distributed to blood donors at blood banks between June and December 2021 in Region Zealand, Denmark. The index tests were the two questions ‘Have you had troublesome sweating?’ and ‘Have you ever had troublesome sweating?’, which were used to create six single-item algorithms for classifying PHH. The reference test comprised the consensus criteria.

Results
Overall, 1071 (95.9%) of 1083 eligible blood donors completed the index tests. The reference test classified 59 participants as having PHH and 980 as not having PHH, generating a prevalence of 5.7% [95% confidence interval (CI) 4.4–7.3]. The algorithms with the highest combined sensitivity and specificity were algorithm 2 with a sensitivity of 0.94 (95% CI 0.77–0.99) and specificity of 0.94 (95% CI 0.92–0.95), and algorithm 5 with a sensitivity of 0.94 (95% CI 0.80–0.99) and specificity of 0.92 (95% CI 0.90–0.94).

Conclusions
With high diagnostic accuracy, these items allow for the identification of individuals with and without PHH, which may prove useful in epidemiological research. Validation in the general population is warranted.