ANKYLOSING-SPONDYLITIS - AN ANALYTICAL REVIEW OF 1500 PATIENTS - THE CHANGING PATTERN OF DISEASE

  • 1 August 1988
    • journal article
    • review article
    • Vol. 15  (8) , 1234-1238
Abstract
To avoid biases inherent in the study of referral patients seen at a single unit, we investigated a group of 1500 patients (males 71%), members of the UK National Ankylosing Spondylitis Society (NASS). Patients were divided into 15 cohorts by year of onset (mean size 91). The median delay in diagnosis for these cohorts was greater than 6 years until 1974. Thereafter, there was a marked improvement with the most recent cohort waiting a median of 2 years for diagnosis (e.g., 1969/72 cohorts vs 1979/82 cohorts; mean delay 7.4 years vs 2.3 years, p < 0.0001). Until 1974 the median delay for women was 9 years compared to 6 years for men (e.g., 1956/62 cohorts 11 and 7 years, p < 0.0015, falling to 3 and 2.5 years, respectively by 1979/82, p = NS). Major differences were seen when the 14 health regions were taken separately; the median delay ranged from 9 years for the 3 "worst" regions to 4 years for the 3 "best" (p = 0.022). This was reflected in the percentage with delay in diagnosis longer than 2 years (80 and 58%, respectively; .chi.2 = 11.31, p < 0.01). Strikingly, the median age of onset of symptoms steadily increased from 18 years in 1930/40 to 28 years in 1981/82 (e.g., 1956/62 vs 1969/72; mean ages 21.4 vs 23.5 years, p < 0.004 and 1969/72 vs 1979/82; 23.5 years vs 28.7 years p < 0.001). In addition, in a case controlled analysis of 387 patients matched for disease duration (18-20 years), the data revealed an inverse relationship between age at onset and need for total hip replacement (THR). Cohorts 10-15 years (juvenile), 18-20 years (early) and 30-40 years (late); THR in 16, 10 and 1%, respectively (juvenile vs late, p < 0.001; early vs/late, p < 0.01). In conclusion, the delay in diagnosis of AS has dramatically improved; the disease may now present with a later age at onset; and this could result in less functional loss as determined by severe hip disease and need for THR.