Age related prevalence of hand osteoarthritis diagnosed by photography (HOASCORE).

BACKGROUND: Hand photography has been used in a number of studies to determine the presence and severity of hand osteoarthritis (HOA). The aim of this study was to present age and gender specific prevalences of HOA diagnosed by this method.

METHODS: Six thousand three hundred forty three photographs (from 3676 females and 2667 males aged 40-96) were scored for hand osteoarthritis by a 0-3 grade (0 = no evidence of OA, 1 = possible OA, 2 = definite OA and 3 = severe OA) for each of the three main sites, distal interphalangeal joints (DIP), proximal interphalangeal joints (PIP) and thumb base (CMC1). An aggregate score of 0-9 was thus obtained (HOASCORE) to reflect the severity of HOA in each case.

RESULTS: DIP joints were most commonly affected, followed by the thumb base and the PIP joints. Having definite DIP joint OA starts at a younger age compared with the other two sites, and there is a marked female preponderance in the age groups from 55 to 69, but after 70 the gender differences are less marked and the prevalence is fairly stable. PIP joint prevalence also indicates a female preponderance from 60 to 79. Thumb base OA has a more marked female preponderance and a rising prevalence thoughout life. The prevalence of individuals with no evidence of photographic OA (HOASCORE = 0) drops from 88% to 57% between the age categories 40-49 and 50-54 and decreased to 33% in the 70-74 age group with a slower decline after that age. DIP and PIP prevalence were strongly associated with each other with an OR of 16.6(12.8-21.5),p < 0.001 of having definite OA at the other site. This was less marked for the thumb base with an OR of 2.2(1.8-2.7, p < 0.001), and 2.7(2.0-3.5, p < 0.001) of having definite DIP or PIP HOA respectively.

CONCLUSIONS: The prevalence of hand OA in DIP, PIP and thumb base joints obtained by the photographic HOASCORE method is higher in women and increases after the age of fifty. These results are in line with those obtained by clinical examination and radiography. The advantage of the method lies in easy applicability and low cost.