Influenza and morbidity and mortality risk in patients in Mexico with systemic arterial hypertension alone or with comorbidities: a retrospective, observational, cross-sectional study from 2014 to 2020.

Abstract

In Mexico, patients with systemic arterial hypertension (SAH) are excluded from the influenza vaccination programme despite their risk of cardiovascular events as influenza-related complications. We investigated the impact of influenza on morbidity and mortality in patients with SAH. This was a retrospective cross-sectional study that analysed data from early 2014 to mid-2020. Data were obtained from the Influenza Epidemiological Surveillance System in Mexico database. 32 663 cases of influenza in people aged ≥20 years with a confirmed case of influenza-like illness, severe respiratory infection and/or influenza death were investigated. Influenza deaths, hospitalisation frequency and the impact on hospitalisation and/or death due to influenza by the SAH variate alone and in combination with diabetes, obesity, chronic obstructive pulmonary disease, cardiovascular disease and/or smoking, and by vaccination status were assessed. The hospitalisation frequency increased with age. Notably, 46.0% (15 033/32 663) of confirmed influenza cases had at least one comorbidity, with SAH (19.2%; 6260/32 663) and obesity (18.7%; 6106/32 663) being the most prevalent. Most confirmed SAH cases (80.8%; 5057/6260) were in those who had not been vaccinated against influenza. There were 3496 deaths due to influenza (mortality rate, 0.69×1 00 000 inhabitants), with the highest rates seen in those aged ≥80 years (80-89 years, 2.0%; ≥90 years, 3.6%). The case fatality rate due to influenza and SAH was significantly higher than those due to influenza without SAH in those aged <50 years, but not in the other age groups (20-29 years, 9.8%, p<0.0005; 30-39 years, 8.2%, p<0.035; 40-49 years, 17.8%, p<0.0005; vs 15.1%-20.0%, p=0.31-0.99 for those aged ≥50 years). Our findings support the need to include SAH in public policies of influenza vaccination as a secondary prevention measure to avoid fatal outcomes.