COVID-19 in Relation to Polypharmacy and Immunization (2020-2024)

Abstract

Background: Observational studies reported worse COVID-19 evolution in relation to polypharmacy and reductions in COVID-19 hospital admissions and death in patients receiving chronic antihistamine treatment. The current profile of hospitalized patients with regard to different variants was analyzed to identify specific targets for future prospective trials.

Methods: COVID-19 admissions to the Hospital of Terrassa (11 March 2020-28 August 2024 (n = 1457), from the integral Consorci Sanitari de Terrassa population (n = 167,386 people) were studied. Age, gender, the number of chronic treatments (nT), and immunization status were analyzed.

Results: After 5 May 2023, 291 patients (54% females) required COVID hospitalization. Of these, 39% received >8 nT (23% receiving 5-7 nT), 70.2% were >70 years, and 93.4% survived. In total, 12% of patients admitted after 5 May 2024 were not vaccinated, while 59% received ≥4 vaccines (43% within the last 12 months). In total, 49% of admitted patients presented no previous infection (while 3% presented infection during the last year). Delta or Omicron variants would have accounted for ≥80% of admissions > 60 years compared to the first pandemic wave if no vaccines existed.

Conclusions: Patients > 70 years who receive ≥5 nT, without prior COVID-19 infections, should be the priority for prevention, with updated vaccination and early treatments to reduce hospitalizations.

Trial registration: ClinicalTrials.gov NCT05504057.

Keywords: COVID-19; death rate; hospital admission; polypharmacy; vaccination.

Figure 1

The numbers of patients who died from COVID-19 are shown in grayscale, the numbers of surviving patients aged under 60 years are illustrated in cold colors (green-blue) in relation to the number of chronic treatments received (nT: 0, 1, 2–7 or ≥8), and the numbers of surviving patients aged over 60 years are shown in warm colors (yellow-orange-red) in relation to the number of chronic treatments received (nT: 0, 1, 2–7 or ≥8).

Figure 2

The distribution of hospital admissions every 15 days for each month in the Terrassa Hospital after 5 May 2023. Warm colors (yellow-orange-red) correspond to patients aged over 60 years, and cold colors (green-blue) correspond to patients aged under 60 years in relation to the number of chronic treatments received (nT: 0, 1, 2–7 or ≥8).

Figure 3

Profile of hospital-admitted patients during and after the pandemic in terms of polypharmacy (see the color scale and percentages for nT), gender, and age.

Figure 4

Estimations of COVID-19 deaths in patients aged over 60 years (black columns) or below 60 years (gray columns), as well as hospital admissions in those aged over or below 60 years (red and yellow, respectively) in vaccinated (VAC) and unvaccinated (NO VAC) patients for the different COVID-19 variants (predominating in >80% of the samples). Since vaccination was registered in 90% of the population aged over 60 years, we assume that the data from the unvaccinated patients correspond to 10% of the population and that estimations for a scenario in which no vaccines existed would be obtained by multiplying the data by ten. The estimations are squared. Note that the number of hospital admissions would have been comparable to that of the first wave.

Figure 5

Vaccine-induced immunization (A,B). Time elapsed from the last vaccination, expressed in years (y), months (m), or days (d) per period and for each variant (A) and the corresponding percentage (B). Warm colors (red/orange/yellow) correspond to hospital admissions within 12 months after vaccination. (C) Percentages of hospital-admitted patients are grouped according to the number of vaccines they had received.

Figure 6

Natural immunization. (A) The time elapsed from the last COVID-19 infection registered in primary care to hospital admission. Some patients had a new infection recorded in primary care facilities after hospital admission (12%, shown in dotted gray). Some primary care records coincided with the day of hospital admission (0 d, shown in striped gray), while the records corresponding to between 1 and 19 days (in green) most likely reflect the symptom onset and should not be considered a new infection (12% if considered altogether). Blue colors correspond to infections within the same year (3%, 2–12 months before hospital admission), while yellow-to-red colors correspond to previous COVID-19 infections occurring between 1 and 3 years ago (24%). (B) Distribution of natural immunity during specific periods and for specific variants.