Linking numeracy and asthma-related quality of life

To examine the correlation of numerical skills used in patients' self-management of asthma with asthma-related quality of life (AQOL).

Adults with moderate-severe asthma completed the Asthma Numeracy Questionnaire (ANQ), assessments of reading comprehension and self-efficacy, and the mini-Asthma Quality of Life Questionnaire (miniAQLQ). The numeracy-AQOL relationship was evaluated in the context of potential confounders (demographic variables) and mediators (e.g. income and self-efficacy), using tests of correlation then multivariable models to assess for confounders and mediators.

80 adults with moderate or severe asthma were evaluated. Mean ANQ score was 2.3+/-1.2 (range 0-4). ANQ was correlated with miniAQLQ (rho=0.24, p=0.03). This association was sustained (rho=0.27, p=0.02) when controlling for potential confounders significantly associated with AQOL (age, Latino ethnicity). The ANQ-miniAQLQ association was mediated by household income; the correlation was reduced by 81% when adjusting for income (rho=0.05, p=0.65). In contrast, self-efficacy less strongly mediated this association; the correlation was reduced by 26% when controlled for self-efficacy (rho=0.20, p=0.08).

Numerical skills needed for asthma self-management influence AQOL primarily through their impact on income and, to a lesser extent, on self-efficacy.

Adults with asthma will benefit from self-management instructions employing the simplest mathematical constructs whose understanding is confirmed by clinicians.