New York State Cases of Anaphylaxis in Elderly Patients From 2000 To 2010 and Characteristics Leading to Under Recognition

There is limited information on the impact of anaphylaxis, a potentially life threatening allergic reaction, in the elderly. This study explores the factors that contribute to under recognition of anaphylaxis in this age group. A retrospective analysis of hospitalized patients aged ≥65 years in NY from 2000-2010 was conducted using the Statewide Planning and Research Cooperative System (SPARCS), a statewide administrative database. Cases were identified using anaphylaxis ICD-9 codes or an ICD-9–based diagnostic algorithm incorporating the National Institutes of Allergy and Infectious Disease (NIAID) diagnostic criteria. Cases identified by the algorithm method likely represent missed cases of anaphylaxis. Multinomial regression analysis was used to model selected variables associated with ascertainment method. Of the 3,673 hospitalizations analyzed, anaphylaxis ICD-9 codes identified 1790 (48.7%) cases, the algorithms identified 1701 (46.3.%) and 182 (5.0%) were identified by both. Age ≥85 and 75-84 were 2.4 (95% confidence interval 1.92-2.90) and 1.4 (95% CI 1.25 – 1.69) times more likely to be in the Algorithm group, respectively. Males were 1.2 times more likely to be included in the Algorithm group (95% CI 1.06-1.41). African Americans, other race and unknown were 1.8 (95% CI 1.52-2.24), 1.4 (95% CI 1.09-1.79) and 1.6 (95% CI 1.10-2.44), times more likely, respectively, to be included in the Algorithm group. Asians were 0.6 times less likely to be included in the Algorithm group (95% CI 0.39-0.98). Being of older age, male and of minority race were associated with increased likelihood of having unrecognized inpatient anaphylaxis.