Preventing and Treating Hospital-associated Infections in Elderly Patients

April 14, 2009
Melissa L.P. Mattison, MD

MDNG Hospital Medicine, February/March 2009, Volume 3, Issue 1

One important aspect of medical care for the elderly is enacting strategies to prevent infections before and during hospitalization.

It is no secret that the elderly are a fast-growing segment of our population, with the number of people age 65 years and older in the United States predicted to exceed 70 million by 2030. People are living longer, and the number of people who are age 85 years and older is expected to triple in the coming years (http://pewhispanic.org/files/reports/85.pdf; www.cdc.gov/Aging/pdf/saha_2007.pdf). Today, the elderly consume more than half of all healthcare expenditures in the US. Addressing the unique health needs of this growing population is vital. One important aspect of medical care for the elderly is enacting strategies to prevent infections before and during hospitalization.

Preventing illness and subsequent hospitalization in the elderly is critical to maintaining a healthy population and decreasing the cost to society. A low-cost and effective method of intervention is the use of vaccinations. Two major vaccinations recommended for older persons are the pneumococcal vaccine and influenza vaccine.

Pneumococcus and influenza account for significant morbidity in the elderly, and the risk of infection and subsequent complications can be greatly reduced by vaccination. The pneumococcal vaccine is recommended by the CDC in all patients age 65 years and older. Most patients need only one shot, though some experts recommend a booster after five years (contraindications for the influenza and pneumococcal vaccinations exist; to see complete information on recommendations, visit www.cdc.gov). A 1997 study published in the Journal of the American Medical Association found that pneumococcal vaccination in the elderly prevented illness, bacteremia, and saved lives. Significant cost savings were also realized. Like pneumococcus, influenza carries significant morbidity and risk of death. Although the efficacy of influenza vaccination is not completely characterized, and may be variable from year to year, an annual influenza vaccination is recommended by the CDC for all patients age 50 years and older.

Hospital-associated infection and the elderly

The elderly account for more than 40% of all patients in acute care hospitals. While hospitalized, the elderly are vulnerable to such infections as healthcare-associated pneumonia (HCAP), urinary tract infections, and antibiotic-associated diarrhea.

Older patients are more at risk for infections than younger patients because they often have chronic organ dysfunction, such as heart failure, chronic kidney disease, and chronic lung disease. The presence of multiple comorbidities places the elderly at risk for impaired immune function, poor nutritional status and reserve, and decreased ability to clear secretions. These factors contribute to an increased risk for respiratory and other types of infections. Elderly patients are frequently prescribed indwelling urinary catheters at a rate at least equal to the 15-25% of the general hospital population who have these devices. One cause for this increased use is that the elderly are more likely to suffer from urinary incontinence. Use of catheters over a prolonged period of time makes it more likely that the patient will suffer from bacterial colonization and ultimately symptomatic infection necessitating antimicrobial use.

Older patients are also at risk for developing healthcare-associated pneumonia. HCAP is a relatively new term that refers to any pneumonia that develops during hospitalization or within 90 days after discharge. HCAP also refers to any case of pneumonia in a resident of a long-term care facility, a patient who receives chronic hemodialysis at a dialysis center, and anyone who receives chronic wound care or has been exposed to someone with a drug-resistant pathogen. Older patients are particularly vulnerable to HCAP for a variety of reasons, including that they are more likely to suffer from chronic lung disease, frequently have diminished gag reflexes, disproportionately suffer from delirium during hospitalization (placing them at risk for aspiration), and may have poor nutrition.

Another dangerous form of infection is diarrhea. Patients who receive antibiotics for treating the primary condition that leads to their hospitalization, or those who receive antibiotics for infections related to their hospitalization, are at increased risk for developing antibiotic-associated diarrhea, including Clostridium difficile, which causes significant morbidity and causes a range of symptoms that include diarrhea, fever, abdominal distention, and death from severe pseudomembranous colitis. Diarrhea among hospitalized patients increases Length of stay and cost of care.

Limiting hospital-associated infection

Although not all hospital-associated infections are preventable, measures can be taken to reduce their frequency and impact. For instance, avoiding the use of indwelling urinary catheters unless absolutely necessary would decrease catheter-related urinary tract infections. Incontinence alone should, in most situations, not necessitate placement of a catheter. Scheduled toileting and the use of absorbent undergarments can often provide an adequate solution to assisting incontinent patients. If a urinary catheter is felt to be medically necessary to accurately measure urine output, it is optimal to remove the catheter as soon as this need no longer exists.

Measures that decrease a patient’s length of stay will help reduce the chance of developing a hospital-associated infection. Recognizing a frail elderly patient early during hospitalization and addressing unique concerns proactively might decrease the duration of hospitalization. Older patients are prone to suffering from delirium at the time of hospital admission or developing it during their stay. Identifying and limiting factors contributing to the delirium can decrease the patient’s length of stay. Hospitalists should strive to minimize older patients’ exposure to potentially inappropriate medications, such as sedative hypnotics—benzodiazepines, anticholinergics (eg, diphenhydramine), and narcotic analgesics. These medications should be avoided, because older patients are particularly vulnerable to their cognitive side effects. Decreasing the use of tethers (eg, telemetry leads, intravenous lines, and restraints) and ensuring adequate sleep in the hospital will help avoid and treat delirium.

Older patients are frequently at risk for aspiration, which increases the risk of HCAP. Assessing and treating patients with poor nutrition or altered mental status for risk of aspiration can help decrease this risk. Measures one might take to mitigate aspiration risk include maintaining good oral hygiene, keeping the head of the bed elevated to at least 30 degrees, providing supervision at mealtime, and obtaining a formal swallow evaluation.

Judicious use of antibiotics is also warranted, as they are associated with additional infections and colonization with resistant pathogens. For example, use of antibiotics can change bowel flora and increase the risk of C. difficile infection. Limiting the use of antibiotics and tailoring antibiotic choice to the narrowest agent possible will help reduce these problems.

Decreasing morbidity and cost

Hospitalization puts all patients at risk for functional decline. Studies have shown that older patients are more likely than younger patients to suffer from physical decline related to hospitalization. For this reason, although any additional illness or infection during hospitalization should be avoided, either might have a particularly negative impact on older patients and their ultimate recovery.

Caring for hospitalized elders can be challenging. Some hospitalizations can be prevented by simple vaccination. Although hospitalists are unlikely to meet a patient prior to hospitalization, admission is an ideal time to address and update vaccinations. Once a patient is hospitalized, physicians and care providers should take measures to decrease the risk of hospital-associated infections. Minimizing delirium, addressing nutrition and risk of aspiration, and using antibiotics only when necessary should help decrease morbidity and overall healthcare costs.

Melissa L.P. Mattison, MD, is an academic hospitalist at Beth Israel Deaconess Medical Center and is an Instructor in Medicine at Harvard Medical School.