10.24265/horizmed.2024.v24n3.04

Original Article

 

Influenza-like illnesses in the Peruvian health system

 

Walter Enrique   Prudencio León *¹,² 0000-0002-2514-5818

María Verónica   Changano Rodríguez ¹ 0000-0003-3508-3179

 

¹.Hospital Central FAP (Central Hospital of the Peruvian Air Force). Lima, Peru.

².Universidad Peruana Unión, School of Human Medicine. Lima, Peru.

 

a. Epidemiologist

b. professor of Epidemiology

c. master’s degree in Public Health

 

ABSTRACT

Objective: To determine the behavior and healthcare trends of influenza-like illnesses (ILIs) in the Peruvian health system from 2018 to 2022.

Materials and methods: An observational, descriptive, retrospective study which analyzed the behavior of healthcare visits for ILIs in Peru, using the open database of Superintendencia Nacional de Salud (SUSALUD - National Superintendency of Health). The variables included diagnoses compatible with ILIs according to the International Classification of Diseases, 10th Revision (ICD-10), age groups, sex, location and period of care. The statistical analysis was performed using Microsoft Excel 365 and Stata 18.

Results: Between 2018 and 2022, ILIs generated an average of 2,576,325 outpatient visits per year (range: 1,790,821- 3,710,299), which accounted for 4.9 % of all outpatient visits in the Peruvian health system. Fifty percent of outpatient visits for ILIs occurred at the Ministry of Health (MINSA) services; in contrast, 51 % of emergency department visits for ILIs occurred at the Seguro Social de Salud (EsSalud - Social Security Health Insurance) services. Emergency services recorded 1,077,584 visits annually (range: 312,306-1,644,758), coded according to ICD-10, which accounted for 15 % of all causes treated in these services. Meanwhile, hospitalization services reported 56,587 hospitalizations per year (range: 46,338-67,233), representing 2.9 % of all hospitalizations in the Peruvian health system, where 60.6 % of ILI-related hospitalizations were in MINSA’s services.

Conclusions: In the Peruvian health system, ILIs pose a recurrent healthcare problem each year, with the health services of MINSA and EsSalud being the most in demand.

 

Keywords: Influenza, Human; Respiratory Tract Infections; Health Systems; Global Burden of Disease. (Source: MeSH NLM)

 

INTRODUCTION

ILIs pose a significant socioeconomic and morbidity- mortality burden worldwide. It is estimated that between three and five million cases will occur, with many patients experiencing a severe episode ⁽¹⁾. In addition, ILIs are of particular concern among vulnerable populations, as they can lead to epidemic outbreaks and are a common cause of hospitalization and death ⁽²⁾.

Estimates regarding outpatient visits, emergency department visits and hospitalizations for ILIs are very limited in low- and middle-income countries such as Peru. Accurate influenza and ILI disease burden estimates are crucial for informed public health decision-making, as they help national and local decision-makers in monitoring epidemiological trends, planning, allocating resources and promoting influenza vaccination ⁽³⁾.

Influenza and ILIs activities decreased due to public health and social measures implemented in response to COVID-19 ⁽⁴⁾. However, a rebound in influenza virus activity is anticipated, given the relaxation of these public health and social measures and the low population immunity against influenza ⁽⁵⁾. Therefore, monitoring influenza and ILIs activity remains critical in the post-COVID-19 era ⁽⁶⁾.

The Peruvian health system is characterized by fragmentation across financing, insurance and healthcare delivery. The State plays a guiding role through the Ministry of Health (MINSA) ⁽⁷⁾.

This study aims to describe the epidemiology of ILIs within the Peruvian health system from 2018 to 2022. The findings will provide valuable insights into the impact of ILIs on the Peruvian health system and offer clues for decision-making regarding their prevention and mitigation.

MATERIALS AND METHODS

 

Study design and population

An observational and retrospective study was conducted using secondary data, with the aim of characterizing the behavior of ILIs in Peru from January 1, 2018 to December 31, 2022. The database employed in the study was collected from monthly reports submitted by Instituciones Prestadoras de Servicios de Salud (IPRESS - Peruvian Health Service Provider Institutions) to Superintendencia Nacional de Salud (SUSALUD - National Superintendency of Health). The information was accessible via the SUSALUD website ⁽⁸⁾, which includes data reported by institutions affiliated with Sistema Nacional Coordinado y Descentralizado de Salud (SNCDS - National Coordinated and Decentralized Health System), such as the health services from MINSA, Dirección Regional de Salud (DIRESA - Regional Health Directorate), Seguro Social de Salud (EsSalud - Social Security Health Insurance), the Armed Forces and Police Forces medical services, private centers and others.

SUSALUD’s open databases include information on diagnoses, coded according to the International Classification of Diseases, 10th Revision (ICD-10) ⁽⁹⁾. These databases also provide data on the total number of patients seen per month, the type of IPRESS, the location of the healthcare provider (by department, province and district), the period of care (by year and month), and the age and sex of patients treated in outpatient, emergency and hospitalization services.

The study included all registered cases with ICD-10 diagnoses compatible with ILIs, according to MINSA’s standards ⁽¹⁰⁾.

Variables and measurements

ILIs are defined based on ICD-10 diagnoses of any event documented in hospitalization, emergency and outpatient records, in accordance with the criteria established in Health Directive No. 061-MINSA ⁽¹⁰⁾. The conditions were categorized into two groups: upper respiratory infections and pneumonias. These conditions were analyzed according to the following variables: sex (male or female), age (according to SUSALUD classification), the health subsystem in which the cases were treated (MINSA, EsSalud, Armed Forces medical services, private centers and others) and the year of care (2018, 2022). The location (department) where care was administered was used to estimate the cumulative incidence rates.

Statistical analysis

The statistical analysis was performed using Stata 18 for Windows (StataCorp, College Station, TX, USA) and Excel 365 (Microsoft, WA, USA).

A descriptive analysis was conducted, with the variables represented in frequency tables showing both absolute and relative percentages. For the inferential analysis, a chi-square test was performed, with a significance level set at p < 0.05.

Ethical considerations

Since secondary data (open data) were used and were publicly available on the SUSALUD website, the study was not submitted for review by an ethics committee.

RESULTS

Outpatient visits

ILIs in the Peruvian health system generated an average of 2,576,325 outpatient visits per year (range: 1,790,821-3,710,299), which accounted for 4.98 % (range: 2.11 %-7.03 %) of all outpatient visits in SUSALUD over the five-year evaluation period. The years with the lowest number of visits were the COVID-19 pandemic years, i.e., 2020 and 2021, representing 2.11 % and 4.48 % of the total outpatient visits, respectively. Differences were found in rates across departments and years of care (p = 0.01), with the lowest rate recorded in Lambayeque (380 cases per 100,000 inhabitants) and the highest in Cajamarca (48,382 cases per 100,000 inhabitants) (Table 1). The female sex accounted for 55.3 %. Children under five years of age accounted for 30 % of ILI cases, while individuals over 65 years of age accounted for 8.25 % (Table 4). Pneumonia was diagnosed in 1.3 % of ILI cases, and 50.45 % were treated in MINSA’s services. The estimated annual rates of ILIs by region showed significant differences between the coast, highlands and jungle (p = 0.01), with the lowest rate of outpatient visits for ILIs on the coast (2,949 cases per 100,000 inhabitants) in 2020, and the highest rate in the highlands (14,112 cases per 100,000 inhabitants) in 2019 (Table 5).

 

Table 1.Number of visits and rates of ILIs in outpatient services across departments and years of care

 

 

Emergency department visits

An average of 1,077,584 emergency department visits for ILIs were recorded each year (range: 312,306-1,644,758), representing 15 % of all emergency visits. Pneumonia was diagnosed in 5.5 % of ILI cases, and 51 % of the patients were female. Children under five years of age accounted for 32.67 % of ILI cases, while individuals over 65 years of age accounted for 7.93 % (Table 4). A total of 51.32 % of emergency department visits for ILIs were registered in services affiliated with EsSalud. Differences were found in rates across departments and years of care (p = 0.01), with the lowest rate recorded in Lambayeque (164 cases per 100,000 inhabitants) and the highest in Moquegua (14,347 cases per 100,000 inhabitants) (Table 2). The estimated annual rates of emergency department visits for ILIs by region showed significant differences between the coast, highlands and jungle (p = 0.01). The highlands recorded the lowest rate of emergency department visits for ILIs in 2020, with 610 cases per 100,000 inhabitants, whereas the coast reported the highest rate in 2018, with 6,883 cases per 100,000 inhabitants. These results are presented in Table 5.

 

Table 2. Number of visits and rates of ILIs in emergency services across departments and years of care

 

 

 

Hospitalizations

In the Peruvian health system, an average of 56,587 hospitalizations for ILIs were recorded each year (range: 46,338-67,233), representing 2.9 % of all causes of hospitalization. Pneumonia was diagnosed in 79.8 % of ILI cases, and 55 % of the patients were male. Children under five years of age accounted for 23.7 % of hospitalized patients, while individuals over 65 years of age accounted for 32 % (Table 4). A total of 60.6 % of patients hospitalized for ILIs were treated in services affiliated with MINSA. Differences were found in rates across departments and years of care (p = 0.01), with the lowest rate recorded in Tacna (8 cases per 100,000 inhabitants) and the highest in Ica (495 cases per 100,000 inhabitants) (Table 3). The estimated annual rates of hospitalizations for ILIs by region showed significant differences between the coast, highlands and jungle (p = 0.01). The jungle recorded the lowest rate of hospitalizations for ILIs in 2019, with 14 cases per 100,000 inhabitants, whereas the coast reported the highest rate in 2018, with 244 cases per 100,000 inhabitants. These results are presented in Table 5.

 

Table 3.Number of visits and rates of ILIs in hospitalization services across departments and years of care

 

 

 

 

Table 4. Annual range of visits and rates of ILIs across age groups (2018-2022)

 

 

 

 

Table 5. Number of visits and rates of ILIs in outpatient, emergency and hospitalization services across regions (coast, highlands and jungle) and years of care

 

 

 

 

 

DISCUSSION

This study aims to estimate ILI disease burden within the Peruvian health system. Over the past five years, ILIs have resulted in 7,714 outpatient visits, 3,227 emergency department visits and 169 hospitalizations per 100,000 inhabitants. The highest ILI burden was observed in children under five years of age, aligning with the international literature ^(5,11). However, comparisons should be made cautiously, as case definitions varied across studies, and in some cases the results from some hospitals were extrapolated to provincial or national levels ^(12,13). In emergency departments, ILIs accounted for 15 % of all visits.

ILIs ^(14,16) are highly infectious diseases, estimated to cause three to five million severe cases and 290,000 to 650,000 deaths worldwide each year ⁽¹⁷⁾. Annual estimates highlight the continuous evolution of influenza and its seasonal variability, underscoring the importance of using ranges to more accurately reflect its annual burden ^(18,19).

ILI burden estimates the number of individuals who fall ill and seek care through outpatient, emergency and hospitalization services, or die within a given period ⁽²⁰⁾. The variability of ILIs makes it difficult to assess their overall impact on the health system ⁽²¹⁾. This study evaluated five years of data, including three years within the COVID-19 pandemic, though these were not considered in our study.

The present study seeks to estimate ILI burden within the Peruvian health system, providing disease-specific burden estimates over the five-year evaluation period. The limitations identified are as follows:

Estimates of visits for ILIs rely on administrative data reported to SUSALUD ⁽²²⁾, making them susceptible to biases such as diagnostic coding errors or underreporting, which could affect burden estimates ⁽²³⁾.

Healthcare-seeking patterns ⁽²⁴⁾ changed with the onset of the COVID-19 pandemic and its overlap with ILIs, as well as due to the implementation of preventive public health measures such as social distancing and mask use ⁽²⁵⁾ and school closures during the pandemic. These factors likely influenced the dynamics of ILIs.

Another limitation is that ILIs can be caused by various pathogens, both viral and bacterial, while influenza infections can lead to illnesses that do not meet the ILI definition ^(26,28). This proportion has exceeded 50 % during peak influenza transmission ⁽²⁹⁾.

Despite its limitations, the study provides a straightforward and timely assessment of ILI burden, offering valuable insights into economic and social costs and contributing to public health decision-making ⁽³⁰⁾.

In conclusion, the results of this study demonstrate that ILIs represent a considerable burden for the Peruvian health system. Estimating the annual burden can enhance surveillance efforts for ILIs, assess vaccination impact, improve epidemiological understanding, and strengthen preparedness for future influenza pandemics.

 

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Author contributions: WEPL conceived, designed and wrote the manuscript, and also approved its final version. Additionally, WEPL and MVCHR performed the required statistical analyses and critically reviewed the contents.

Funding sources: The article was funded by the authors.

Conflicts of interest: The authors declare no conflicts of interest.

 

Corresponding author:

Walter Enrique Prudencio León

Address: Avenida Andrés Aramburú cuadra 2 s/n, Miraflores. Lima, Perú.

Telephone: +51 999 671 847

E-mail: wpl29@hotmail.com

 

Reception date: December 20, 2023

Evaluation date: February 19, 2024

Approval date: February 28, 2024