The Adapted Classification of Male Pattern Hair Loss Improves Reliability

Abstract

Background: The Hamilton-Norwood classification (HNC) is used to assess the severity of pattern hair loss (PHL). Conflicting associations between PHL and cardiovascular disease (CVD) have been reported from studies that used different methods to assess alopecia severity. No classification including the HNC has been validated for population studies. We aimed to simplify the HNC, produce the adapted HNC and test its reliability for use in population studies. Methods: Identifying vertex alopecia as distinct allowed for a simpler alignment of alopecia figures where scores 4V and 5V in the adapted HNC replace IV and V in the original HNC. The two classifications were to be used by twelve of our staff (secretaries, nurses, dermatology trainees and dermatologists) to evaluate 16 men with PHL. Observer agreement was estimated using intraclass correlation coefficient (ICC) and a percentage method duplicated from the recent basic and specific (BASP) classification. Results: The ICC improved with the adapted HNC when assessed by both the nurses/secretaries (from 0.47 to 0.61) and dermatology residents/consultants (from 0.68 to 0.76). Agreement using the BASP percentage method for dermatologists was 62–69% for the original and 93–100% for the adapted HNC. Conclusions: The adapted HNC increased reliability at various staff levels, making it suitable for epidemiological studies; its use in future studies could help elucidate the association between PHL and CVD.

Modified basic and specific (BASP) classification for pattern hair loss

“…The BASP classification can easily be applied to both sexes and so has been widely utilized since its proposal by Lee et al . in 2007 . The BASP classification has been used in follow‐up studies and has also proven useful .…”

“…released a more comprehensive basic and specific (BASP) classification that overcame the shortcomings mentioned above and can be widely used regardless of race or gender. The BASP classification is widely used in both clinical and research settings …”

Classification of male-pattern hair loss

“…Currently, Norwood-Hamilton classification is the most widely used hair loss classification. [ 8 9 ]…”

“…The type IIA that was present in the original Norwood-Hamilton was removed for simplification. Types VI and VII also do not have additional classification designation as the hair loss on these types involves both anterior (A) and vertex (V) [ Figure 3 ][ 8 ].…”

“…Moreover, this system is easy to learn, memorize, practice and has better reproducibility than the previous classifications in routine clinical practice. [ 5 8 9 12 ]…”