Table of contents

Editorial
Meet the team
Dr Alan Walker
Original Contribution/Clinical Investigation
The discriminative value of two functional assessment scales compared for predicting falls in institutionalized elderly people in Iran
The relationship between depression and educational levels, the retirement years and chronic diseases of elderly men in area 6 of Tehran's municipality 2005
Evaluating Infectious Etiologies of Hospitalization in Elderly Population of Iran
Models and Systems of Elderly Care
The Economic Impact of Treating Geriatric Hip Fracture - A Study at Rustaq Referral Hospital , South Batinah Region, Oman
Clinical Research and Methods
Acceptable Satisfaction after Carpal Tunnel Decompression in Elderly Patients

 

Evaluating Infectious Etiologies of Hospitalization in Elderly Population of Iran

Authors
1. Mardani M.*
2. Keshtkar Jahromi M*.
3. Mir Eshghi M.*

* MD, Infectious Diseases and Tropical Medicine Research Center, Shaheed Beheshti Medical University, Tehran, Iran

Correspondence:
Masoud Mardani, MD
Address: Infectious Diseases and Tropical Medicine Research Center, 7th floor, Faculty of Medicine, Shahid Beheshti Medical University, Tabnak Avenue, Evin, Chamran Highway, Tehran, Iran
Email: mmardani@hotmail.com
Phone: +98 21 8836 6941
Fax: +98 21 8897 2566


Abstract:

Background and Objectives: Regarding the increase in life expectancy in geriatric population, we decided to perform a study to evaluate infectious causes of hospitalization in elderly patients in 3 infectious wards in Tehran.

Methods: Medical Records of 667 hospitalized elderly patients (>65 year old) were reviewed retrospectively since March 2003 to March 2004. Data was analyzed by SPSS 12.

Results: Most admissions (Mean age of 75 years) were in summer and fall. Respiratory tract infections (RTIs) were the most common cause of admission in infectious wards (41.4%). Other common causes were as follows respectively: Urinary Tract Infections (21.9%), Sepsis (9.3%), Gastrointestinal Infections (7.8%), Non-infectious etiologies (4.9%), Skin and Soft tissue Infections (4.3%), Tuberculosis (3.4%), Septic Arthritis (1.9%), Hepatitis (1.6%), Meningitis (1%), Fever of Unknown Origin (0.9%), Endocarditic (0.4%). and 0.9% Expired before diagnosis. 92.1% of patients survived and 7.9% expired. Sepsis was the most common infectious etiology of death (45.2%).

Conclusion: RTIs are the most common causes of elderly hospitalization in infectious wards of Iran. Infectious wards are mostly crowded in summer and fall. These results mandate special care for prevention of respiratory tract infections such as vaccination and planning other preventive measures required for the elderly population in Iran.

Keywords: Elderly, Hospitalization, Infection

Introduction

Compared with the younger population, the elderly have increased susceptibility to infection and are at significantly increased risk for morbidity and mortality due to many common infections [1]. Possible explanations for the observed higher morbidity and mortality rates among older patients include low physiological reserves due to the biologic changes that accompany aging and the frequent presence of comorbid illnesses. Morbidity and mortality rates also are influenced by age and comorbidity-related decremental changes in host defenses. Also delays in diagnosis and initiation of appropriate treatment due to atypical presentation may lead to increased morbidity and mortality [2].

Demographic aging is now well established, and the elderly population (age, >65 years) will exceed 1 billion persons in 2030 [3]. To date, the projection of population aging predicts that the proportion of elderly individuals will be as great as 19.6% and 23.0% of the population in North America and Europe, respectively, compared with 4.6% in Africa and 11.5% in both Asia and Latin America. However, these proportions are changing [3], and in 2030, more than three-quarters of the elderly population are predicted to live in developing countries.

It is projected that, in 2020, three-quarters of all deaths in developing countries could be due to age-associated diseases. These are predominantly non-communicable diseases, such as cardiovascular disease, cancer, and diabetes. What is the role of infection in the death of elderly individuals? Statistics from the WHO [4] suggest that, in Europe and the United States, 5% of the population >60 years old will die as a consequence of infection, compared with 20% in Africa.

Although demographic aging does not remain restricted to industrialized countries, the medical challenge arising from the aging population will be distinct in the developing world. This is particularly true with respect to infectious diseases, which have a distinct spectrum in the elderly population, as well as a greater overall relevance in the developing world. Tropical diseases have a specific presentation and epidemiology in elderly patients. Infectious diseases with a worldwide distribution impact elderly patients in the developing world in a specific manner, which is most obvious with respect to human immunodeficiency virus and tuberculosis but is also true with respect to "trivial" manifestations of infection, such as diarrhea and pneumonia. Malnutrition contributes in a major way to the immunodeficiency of elderly patients in the developing world. Poorly controlled use of antimicrobial drugs leads to multidrug-resistant microorganisms, which, together with the limited resources available for drug treatment, makes appropriate treatment of infections in elderly patients in developing countries very difficult. Infections in elderly patients will have an increasing impact on the public health and economy of developing countries [3]

This study is designed to determine common infectious etiologies of hospitalization in elderly populations of Iran as a developing country in the Middle East region.

The results of this study are useful for planning of preventive care and a special policy for hospital beds required for common infectious diseases leading to hospitalization in this country.


Methods

In this retrospective study, medical Records of 667 hospitalized elderly patients (>65 year old), admitted in teaching infectious wards of Shaheed Beheshti Medical University since March 2003 to March 2004, were reviewed. This university is one of three major universities in the capital of Iran and covers east, north and west parts of Tehran province. Variables including registration number, date of admission, season of admission, age (categorized in 5 years intervals), sex, diagnosis and outcome (survived or expired) were recorded for each patient. Diagnosis recorded for each patient was defined as below: 1. Respiratory tract infections 2. Gastrointestinal tract infections (except for hepatitis) 3. Urinary tract infections 4. Central nervous system infections 5. Tuberculosis (involving all systems) 6. Endocarditis 7. Hepatitis 8. Skin and soft tissue infections 9. Septic Arthritis 10. Fever of unknown origin 11. Sepsis 12. Nonifectious diagnosis and a proportion were expired before diagnosis. Data sheets were completed and analysis was performed by SPSS (version 12).

Results

Data for 667 patients were recorded. 55.8% were male and 44.2% female. Mean age of patients was 75 years (ranging from 65 to more than 95 years). 55.8% were male and 44.2% female.

Respiratory tract infections (276 cases, 41.4 percent) were the most common cause of admission in infectious diseases wards. Other Common causes of hospitalization in infectious wards were as follows respectively: Urinary Tract Infections (146 cases, 21.9 percent), Sepsis (62 cases, 9.3 percent), Gastrointestinal Infections (52 cases, 7.8 percent ), Non-infectious etiologies (33 cases, 4.9 percent), Skin and Soft tissue Infections (29 cases, 4.3 percent), Tuberculosis (23 cases, 3.4 percent ), Septic Arthritis (13 cases, 1.9 percent), Hepatitis (11 cases, 1.6 percent), Meningitis (7 cases, 1 percent), Fever of Unknown Origin (6 cases, 0.9 percent), Endocarditic (3 cases, 0.4 percent) and 6 patients (0.9 percent) were expired before diagnosis.

Most cases were admitted in summer (182 cases, 27.6 percent) and fall (180 cases 27.3 percent). 25 percent were hospitalized in spring, but only 20.1 percent in winter. Most patients with tuberculosis and respiratory tract infections were admitted in fall. GI tract infections, UTI, meningitis and endocarditis admitted mostly in spring. Sepsis, septic arthritis and hepatitis admitted mostly in summer and skin-soft tissue infections in winter. 92.1 percent of our patients were discharged and 7.9 percent were expired during hospital course. Sepsis was the most common cause of death in hospitalized elderly populations (4.2 percent). Other causes for death were: Respiratory Tract Infections (1.9 percent), Urinary Tract Infections (0.6 percent), Tuberculosis (0.3 percent) and 0.9 percent were expired before diagnosis.

Diagnosis specific mortality rate was as follows: Sepsis (45.2) percent, Respiratory Tract Infections (4.7 percent), Urinary Tract Infections (2.7 percent) and Tuberculosis (8.7 percent).

Discussion

Average life expectancy throughout developed countries has rapidly increased during the latter half of the 20th century and geriatric infectious diseases have become an increasingly important issue. Infections in the elderly are not only more frequent and more severe, but they also have distinct features with respect to clinical presentation, laboratory results, microbial epidemiology, treatment, and infection control. Reasons for increased susceptibility include epidemiological elements, immunosenescence, and malnutrition, as well as a large number of age-associated physiological and anatomical alterations (5).

In industrialized countries, pneumonia, urinary tract infections, and skin and soft-tissue infections are the most relevant infections in elderly patients [5, 6, 7]. In 2002, WHO reports that in developing countries, pneumonia is one of the leading causes of death in elderly patients (those >60 years of age).[4]. Studies from South America, India, and Africa investigating the global impact of infections in elderly patients conclude that, compared with industrialized countries, pneumonia, urinary tract infections, and skin and soft-tissue infections are the most relevant infections in elderly patients [5, 6, 7].

Our study is the first that evaluates infectious etiologies of hospitalization in elderly populations of Iran and shows that respiratory tract infections (mostly pneumonia) are the most common cause. This result is compatible with other studies in industrialized and developing countries [5, 6, 7, 8, 9].

In Switzerland, causes of death in a hospitalized geriatric population were evaluated [8]. Macroscopic and histological studies of 3000 consecutive autopsies (43.9 percent of the registered deaths) were performed by the same pathologist in a geriatric institution over a period of 20 years. Bronchopneumonia (42.9), malignant neoplasms mainly of the gastrointestinal tract and its annexae and the lungs (28.1 percent)-pulmonary thrombo-embolism (21.2 percent) and acute myocardial infarction (19.6 percent), were the most prevalent fatal conditions observed. Next, in decreasing order were: urinary tract infection (12.3 percent), acute cerebrovascular disease (6.5 percent), internal haemorrhage (5. percent 5), and congestive cardiac failure (3.3 percent). Some potentially treatable disorders, which led to death were unsuspected clinically: for example, acute pyelonephritis (87 percent), pulmonary thrombo-embolism (74 percent), acute myocardial infarction (74 percent) and active pulmonary tuberculosis (61 percent). We see that the most common cause of death in this study is equal to the most common cause of hospitalization in our study. This correlation shows the significance of pulmonary infections as a common etiology for mortality and morbidity in elderly.

In another study, in Singapore, the presentation of elderly people at an emergency department was evaluated [9]. Patients aged 60 years and above who attended the Emergency Department (ED) at Alexandra Hospital, Singapore, during 4 randomly selected one-week periods in 1996 were retrospectively studied. The 3 most common diagnoses were chest infection or pneumonia (8.2 percent), non-fracture head injury (7.2 percent) and heart failure (6.6 percent). The elderly constituted 12.4 percent of attendance at the ED but formed 34.5 percent of admissions. They were more likely to have emergency problems. They concluded that understanding the common presenting symptoms and diagnoses of the elderly will help doctors at the ED provide better care. The results of this study also show that pneumonia is the most common cause of elderly emergency department admission in Singapore, which is compatible with our results of infectious wards admission in Iran.

Most of our patients were admitted in summer (27.6 percent) and fall (27.3 percent). Unfortunately we did not find any study to compare this finding with it. Although most patients were admitted in summer and respiratory tract infections were the most common cause of admission, but most patients with respiratory tract infections were admitted in fall. It can be explained with the fact that most cases with gastrointestinal tract infections, sepsis and urinary tract infections were admitted in warm seasons (spring and summer).

Mortality rate for respiratory tract infections in our elderly population was 4.7 percent. Torres et al. [10], in a study of 124 patients with chronic obstructive pulmonary disease (COPD) and CAP (mean age ± SD, 67 ± 11 years; 115 males; 2 patients at a nursing home) found that the overall mortality rate was 8 percent. Although the mean age of their patients is similar to ours, but the difference in mortality is mainly explained by their underlying condition (COPD). In another study [11], in-hospital case-fatality rates for pneumonia in the first 10 days of hospitalization and overall was 2.1 percent and 3.2 percent respectively, for 11,684 patient hospitalizations that are nearer to our results.

Mortality rate for sepsis in our elderly population was 45 percent. Multiple prospective studies have shown increasing age to be associated with a high rate of death due to sepsis, independent of severity of illness and presence of comorbid conditions [14, 15]. Angus et al. [16] reported that the overall mortality rate associated with sepsis was 28.6 percent, whereas the rate among patients 85 years of age was 38.4 percent. However, the association between advanced age and an excess number of deaths due to sepsis is not uniformly observed in epidemiological investigations [17]. In a recent study [18] of 406 patients with sepsis, age was a risk factor for in-hospital mortality on univariate analysis; however, on multivariate analysis, this association was no longer seen.

We recorded no mortality for meningitis, endocarditis, fever of unknown origin, gastrointestinal infections, skin and soft tissue infections, septic arthritis and hepatitis. These results are in contrast to other studies[12, 13], which demonstrate increased mortality rate among elderly patients with such diagnoses. This may be explained by the fact that few cases were recorded in these groups in our study.

We conclude that respiratory tract infections are the most common causes of hospitalization in infectious wards in elderly population of Iran. Infectious wards are mostly crowded with elderly patients in summer and autumn. Mortality (45.2 percent due to sepsis) is directly related to the etiology of hospitalization. These results would mandate special care for prevention of respiratory tract infections such as vaccination and planning a special policy for hospital beds required for elderly patients in Iran. Prevention, early recognition, and prompt initiation of empirical antimicrobial therapy are the cornerstones of the strategy to reduce the impact of infectious diseases on older adults.

References

1. Yoshikawa TT. Perspective: aging and infectious diseases: past, present, and future. J Infect Dis 1997; 176:1053 7.
2. Dean C. Norman. Fever in the Elderly. Clinical Infectious Diseases 2000; 31:148- 151.
3. Gaëtan Gavazzi, Francois Herrmann, and Karl-Heinz Krause. Aging and Infectious Diseases in the Developing World. Clinical Infectious Diseases 2004; 39:83-91.
4. World Health Organization. The world health report 2002. Geneva: World Health Organization, 2002.
5. Gavazzi G, Krause KH. Ageing and infection. Lancet Infect Dis. 2002 Nov; 2(11):655.
6. Yoshikawa TT. Epidemiology and unique aspects of aging and infectious diseases. Clin Infect Dis 2000; 30:931 3.
7. Karstaedt AS, Khoosal M, Crewe-Brown HH. Pneumococcal bacteremia in adults in Soweto, South Africa, during the course of a decade. Clin Infect Dis 2001; 33:610 4.
8. Gee WM. Causes of death in a hospitalized geriatric population: an autopsy study of 3000 patients. Virchows Arch A Pathol Anat Histopathol. 1993; 423(5):343-9.
9. Lim KH, Yap KB. The presentation of elderly people at an emergency department in Singapore. Singapore Med J. 1999 Dec; 40(12):742-4.
10. Torres A, Dorca J, Zalacain R, et al. Community-acquired pneumonia in chronic obstructive pulmonary disease: a Spanish multicenter study. Am J Respir Crit Care Med 1996; 154:1456.
11. Thomas J. Marrie, Keumhee C. Carriere, Yan Jin, and David H. Johnson. Factors Associated with Death among Adults <55 Years of Age Hospitalized for Community-Acquired Pneumonia. Clinical Infectious Diseases. 2003; 36:413-42.1
12. Watanakunakorn C, Burkert T. Infective endocarditis at a large community teaching hospital, 1980 1990: a review of 210 episodes. Medicine (Baltimore) 1993; 72:90 102.
13. Kastenbauer S. Pfister HW. Pneumococcal meningitis in adults: Spectrum of complications and prognostic factors in a series of 87 cases. Brain. 2003; 126:1015-1025.
14. Knaus WA, Harrell FE, Fisher CJ Jr, et al. The clinical evaluation of new drugs for sepsis: a prospective study design based on survival analysis. JAMA 1993; 270:1233 41.
15. Gogos CA, Lekkou A, Papageorgiou O, Siagris D, Skoutelis A, Bassaris HP. Clinical prognostic markers in patients with severe sepsis: a prospective analysis of 139 consecutive cases. J Infect 2003; 47:300.
16. Angus DC, Linde-Zwirble WT, Lidicker J, Clermonte G, Carcillo J, Pinsky MR. Epidemiology of severe sepsis in the United States: analysis of incidence, outcome, and associated costs of care. Crit Care Med 2001; 29:1303.
17. Harbarth S, Garbino J, Pugin J, Romand JA, Lew D, Pittet D. Inappropriate initial antimicrobial therapy and its effect on survival in a clinical trial of immunomodulating therapy for severe sepsis. Am J Med 2003; 115:529 35.
18. Garnacho-Montero J, Garcia-Garmendia JL, Barrero-Almodovar A, Jimenez-Jimenez FJ, Perez-Paredes C, Ortiz-Leyba C. Impact of adequate empirical antibiotic therapy on the outcome of patients admitted to the intensive care unit with sepsis. Crit Care Med 2003; 31:2742.