Loading...
Incidence and mortality rates of bullous pemphigoid (BP) appear to be increasing. In the 1990s, five European studies reported annual incidence rates of 6 to 14 cases per million persons; in the U.K. in 2008, that rate was 43 cases per million per year. The authors of a recent French study had previously examined the incidence of pemphigoid patients in the period 1986-1992. They used similar methods to conduct a retrospective cohort study in the same three French regions, comparing BP incidence from 2000 to 2005 with rates in the first study. They also examined related mortality.
In the study period, 542 patients developed BP (305 women; mean age, 82; percentage older than 70, 92%). The overall estimated annual incidence rate of 21.7 cases per million persons is three times the rate identified in the 1986-1992 period. Incidence increased sharply with increasing age: 162 cases/million persons in those 70 or older and 507/million in those 85 and older.
The mortality rate in BP patients rose sharply as well. Of 312 BP patients followed for 12 months, 118 died — a 1-year survival rate of only 62% (95% confidence interval, 56%-67%), and a 6-fold excess mortality rate. Excess mortality was observed at all ages, and was higher in women.
Joly P et al. Incidence and mortality of bullous pemphigoid in France. J Invest Dermatol 2012 Aug; 132:1998.
Naldi L et al. Bullous pemphigoid: Simple measures for a complex disease. J Invest Dermatol 2012 Aug; 132:1948.
Comment
These authors report a threefold increase in BP incidence in a short period. They and editorialists contemplate statistical methods but find no convincing explanation there. Diagnostic methods changed during this period – currently, most clinicians use ELISA assays, rather than direct or indirect immunofluorescence techniques. The simplicity of ELISA assays may have prompted more tests to be ordered and more pemphigoid to be detected.
Regardless, bullous pemphigoid is relatively common, and incidence may be increasing, a phenomenon perhaps attributable to increased longevity, increased use of psychotropic drugs, or inclusion of atypical cases. Neurological diseases increase risk for bullous pemphigoid, and higher prevalence of these disorders in the aged may be related. The 6-fold higher mortality rate cannot be attributed to systemic glucocorticosteroid or immunosuppressant treatment, as most patients were treated without them.