Comparison of influenza hospitalization outcomes among adults, older adults, and octogenarians: a US national population-based study

Abstract

Objectives: This study sought to more fully elucidate the age-related trends in influenza mortality with a secondary goal of uncovering implications for treatment and prevention. Methods: In this retrospective cohort analysis of data from the Nationwide Readmission Database, patients with influenza as a primary or secondary discharge diagnosis were separated into three age groups: 55 638 adults aged 20e64 years, 36 862 adults aged 65e79 years and 41 806 octogenarians aged 80 years. Propensity score (PS) weighting was performed to isolate age from other baseline differences. Crude and PS-weighted hazard ratios (HR) were calculated from the in-hospital all-cause 30-day mortality rate. Admission threshold bias was minimized by comparison of influenza with bacterial pneumonia mortality. Results: Adults aged 20e64 years experienced higher in-hospital 30-day mortality compared with older adults aged 65e79 years (HR 0.66; 95% CI 0.55e0.79). Octogenarians had the highest mortality rate, but this was statistically insignificant compared with the adult cohort (HR 1.09; 95% CI 0.94e1.27). This trend was not explained by admission threshold bias: the 30-day mortality rate due to in-hospital bacterial pneumonia increased consistently with age (older adult HR 1.45; 95% CI 1.32e1.59; octogenarian HR 1.99; 95% CI 1.82e2.18). Conclusions: Adults aged 20e64 years and octogenarians were more likely to experience all-cause 30day mortality during influenza hospitalization compared with older adults aged 65e79 years. These data emphasize the importance of prevention and suggest the need for more tailored treatment interventions based on risk stratification that includes age.

Room for improvement in current influenza vaccines? A systematic literature review on the humanistic and economic burden of influenza in older (≥65 years old) adults

“…Fifteen studies reported the economic burden of seasonal influenza in adults aged [? ]65 years (28,34,35,(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52). The majority of studies (n=7) were conducted in the US (34,(41)(42)(43)(44)(45)(46).…”

“…]65 years (28,34,35,(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52). The majority of studies (n=7) were conducted in the US (34,(41)(42)(43)(44)(45)(46). Very few studies were conducted in other countries of interest, including Spain (n=2) (50,51), China (n=1) (47), France (n=1) (48), Germany (n=1) (49), the UK (n=1) (28), Japan (n=1) (52), and South Africa (n=1) (35).…”

“…All studies reported on direct costs (28,34,35,(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52), however, only three studies presented indirect cost results (29,34,52). Economic study characteristics are presented in Supplementary Table S15.…”

Influenza A-Associated In-Hospital Mortality in Very Older People: Does Inflammation Also Play a Role?

“…In developed countries, there is an evident growth in the octogenarian and nonagenarian population, and a sharp increase is expected in the following years [6]. Notwithstanding the rapid aging of the population, few studies have analyzed the impact of seasonal influenza in the oldest old patients, even though they represent a highly vulnerable group with increased likelihood of worse outcomes [1, 5, 7, 8].…”

“…The risk of influenza-related death increases exponentially after the age of 65, irrespective of underlying comorbidities, and the few studies addressing influenza in octogenarians have reported higher mortality rates than adults between 60 and 80 years [5, 7, 8]. Although the mechanisms leading to increased susceptibility in older people are not fully understood, a common denominator of age-associated frailty is an increased baseline inflammation that can translate into immunologic inhibition [9].…”