How do geriatric patients impact infection control?

As far back as 1979, the elderly have been recognized as a unique patient population for infectious disease prevention and control. In the 1980s, a call came out for increased research focusing on epidemiologic, clinical, and the basic science of aging. The most recent CDC guidelines have begun to address “extremes of age” as a focus of infection prevention and control in Long Term care settings, and the Center for Medicare and Medicaid Services (CMS) has established regulations in this setting as well. However, while the Long Term Care setting has garnered increased attention, there has been little targeted research involving geriatric inpatient units. The IDSA and other national and international organizations have several guidelines for a variety of infection prevention and control issues that are also faced by elderly populations but they do not specifically address the setting of the inpatient Geriatric Unit.

What elements of infection control in the geriatrics unit are necessary for infection prevention and control?

The elderly are a heterogeneous group that are highly susceptible to infections for several reasons – presence of multiple chronic diseases, diminished immune response, malnutrition, polypharmacy, functional impairment and cognitive impairments that may complicate basic sanitary practices like hand hygiene and personal hygiene. Along with cellular and humoral immunity, the “immune system” deficits include weakening in barriers like skin, urethelium, and bronchial mucociliary and airway clearance.

One of the basic principles of Geriatrics is that by limiting certain interventions to the most essential indications and shortest possible durations (including urinary catheterization, intubation and intravascular catheterization) helps reduce the risk of several hospital acquired infections including UTIs, hospital-acquired pneumonia and bloodstream infections. Likewise, actively mobilizing and feeding patients is extremely important.

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Several different types of infection have been studied with varying levels of evidence to support recommendations. Major infectious processes for which we have the most data include urinary tract infections, pneumonia, Clostridium difficile diarrhea, and MRSA infections of blood and various organs. These studies have explored both the prevention of these particular disease processes and optimal strategies to control or treat them if they do occur. There has also been some research around oral care, isolation regulations and antibiotic choices for prevention of infections. Of note none of these trials, prospective and retrospective studies or case reviews were developed focusing on geriatric inpatient units specifically.

Older adults may pose a significant diagnostic challenge as they may not manifest the usual signs and symptoms of infection. Aphasia, hearing loss and cognitive impairment may further complicate the picture. In these settings, historical information provided by family members and caregivers can prove to be very valuable. The same challenge applies to monitoring response to treatment insofar as things like fever curves or white blood count values may be less meaningful than improving mentation and appetite.

What are the conclusions from clinical trials or meta-analyses related to infection control in the geriatrics unit that guide infection control practices and policies?

There are no key conclusions specific to Geriatric Inpatient Units; there are, however, studies examining hospitalized elders, and there are some basic principles that are particularly important for older patients because of their increased risk.

1) Vaccines: evidence going back 25 years cites the importance of vaccinations in the elderly. The three most important immunizations include influenza, pneumococcal, and tetanus/diphtheria toxoid vaccines. Controlled trials in the elderly have shown effectiveness of influenza vaccine at reducing hospitalization rates and deaths that are mostly due to secondary bacterial pneumonia. Pneumococcal vaccine has been found to be cost effective in elderly as per a detailed case study but effectiveness has not been demonstrated in preventing pneumonia. The vaccines do appear to protect older patients from pneumococcal bacteremia, however. These vaccines are somewhat less effective at raising antibody titers and preventing disease in older patients than in younger patients, and antibody titers decline with time. However, the widest possible application of these two vaccines is highly encouraged. Delivery of these vaccines to all older patients and particularly to frail older patients is recommended by the CDC and is a quality measure, tracked by Medicare, the Joint Commission and health plans.

Tetanus has its highest incidence in persons over age 65 in United States and has very high mortality rates once it develops. It is still rare and is incurred primarily by people who lack protective antibodies and are active out of doors, since Clostridium tetani is a soil organism. These are the people for whom vaccination should be emphasized, more so than those who spend all of their time in bed. The importance of inpatient settings is that the sicker, highest risk, older patients are hospitalized, and providers have an opportunity to vaccinate them at the time of admission. Documenting and sharing this information to reduce the occurrence of duplicate vaccination is important though the risk of adverse outcomes after duplicate vaccination is low.

2) Hand Hygiene: sustained decrease in incidence of MRSA and VRE infections in the ICU have been noted with improved hand hygiene. Preventing transmission of infections from one patient to the next is a tried and true basic principle of medicine and has been considered valid for centuries but requires consistent efforts to achieve the goal. Hand hygiene studies continue to show far less than 100% compliance even when foam hand washes are available at the door of patient rooms, which is “best practice” currently.

3) Restrictive antibiotic policy: Clostridium difficile infection has been shown to be successfully controlled through the use of a restrictive antibiotic policy. This involved limited use of cephalosporins, limiting antibiotic duration to 7 days, and involving Infectious Disease specialist consultation as per various studies but there was no reported change in mortality rates and length of hospitalization. There was a significant reduction in C. difficile incidence rate, MRSA colonization rate and cost.

4) Dry Mist Hydrogen Peroxide for eradication of Clostridium difficile: Although hand hygiene has improved, concern over the amount and spread of C. difficile infections in the hospital continues to grow. Guidelines currently recommend a chlorine disinfectant for sporicidal effect when cleaning. Recent studies have suggested, however, that hydrogen peroxide delivery systems may be more efficacious. One study specifically focused on elderly wards found a reduction from 24% to 3% of spores found in the environment after hydrogen peroxide decontamination. This study was very small, and no further data are available regarding widespread use of this new system.

5) Oral Hygiene: There is an increased prevalence of health care acquired pneumonia in elderly patients, and it is the most common cause of death due to nosocomial infections, with a mortality rate of up to 25%. Given the extent of poor oral hygiene found in elderly patients, one mechanism of increased health care service use associated pneumonia could be aspiration of oral pathogens into the lungs. A systematic review of RCTs examining improved oral hygiene and its effect on respiratory tract infections did show decrease in death from pneumonia with specific interventions. The most effective intervention involved weekly professional cleaning with an ARR of 11.7% or NNT of 8.6. This was followed closely by tooth brushing after every meal. The ARR with this intervention was 8.6% and NNT to prevent death from pneumonia was 11.3. These findings have been corroborated by previous reviews providing good evidence that mechanical oral hygiene reduces occurrence of respiratory infections in frail elders and therefore decreases mortality as well.

6) Urinary Tract Infections: The diagnosis of a urinary tract infection is one of the most common reasons for hospital admission in the elderly but is often misdiagnosed given its atypical presentation in elders. Accurate diagnosis and treatment are important to avoid exposure to unneeded antibiotics, prevent development of resistant bacteria, and reduce adverse events associated with antibiotics.

A retrospective case review examining the diagnosis and treatment of urinary tract infections in 265 elders admitted to the hospital found that the diagnostic guidelines used in younger patients did not apply. Fewer than half the patients on case review in the group diagnosed with a urinary tract infection had urinary tract symptoms. There were high rates of asymptomatic bacturia leading to over diagnosis and treatment; no current guidelines support the treatment of asymptomatic bacturia in elderly patients. Furthermore, several patients that did have symptoms had no growth on urinary cultures. This retrospective study also provided evidence for obtaining blood cultures on admission given the overall lack of consistent presentations in this patient population. Overall approximately 40% of cases were incorrectly diagnosed.

Analysis of large samples of post-surgical patients such as those by Wald and colleagues (2008) shows an epidemiologic association between catheterization of the bladder for more than 2 days and doubled rates of iatrogenic urinary infections. A few studies have demonstrated reduced numbers of inappropriate urinary catheters and related infections using reminder systems and other standard protocols, often initiated by nurses. One example is the article by Bruminhent and colleagues (2010). Another is written by Elphern and colleagues (2009) again focusing on removal of catheters that are not clinically indicated with a reduction in urinary infections. Although there are some limitations in methods, these are prospective studies that support the strategy of removing catheters whenever possible.

Countervailing are studies like the one by Loeb and colleagues (2008) in which a randomized trial of catheter removal produced less inappropriate catheter days but no change in infection rate. A recent US review on this topic by Meddings (2010), working with Sanjay Saint who is one of the most published academic geriatricians in this field, indicates a strong argument for minimizing catheter days as a means of reducing iatrogenic urinary tract infections. Finally, with respect to urinary catheters, geriatricians colloquially refer to them as “one point restraints” and remove catheters to promote early and more effective mobilization of patients. Mobilization almost certainly has a number of benefits in regard to incident infections in the hospital as a secondary result of reduced delirium, reduced urethral contamination, shorter length of stay, less aspiration, and less skin breakdown, though this is not easily proven with the available objective data.

Also, with regard to anti-microbial selection, synthesis of current guidelines for treatment of lower urinary tract infections in general adult populations suggest that Bactrim should likely be consider first line, followed by nitrofurantoin, fluoroquinolones, and augmentin. None of these guidelines address elderly patients specifically. Nitrofurantoin is often a poor choice given the likelihood of reduced creatinine clearance (nitrofurantoin has limited excretion into the urinary tract below a clearance of 50 mL/minute). Augmentin (ampicillin plus clavulanate) has been associated with a high incidence of secondary C. difficile infections. Bactrim (trimethoprim-sulfamethoxazole) interacts strongly with warfarin and fairly often causes renal dysfunction. These considerations mitigate against the use of Bactrim as a first line agent in many geriatric cases, despite its favorable antimicrobial profile and concentration in the urinary tract. Again, no formal standards have been developed.

7) Surgical Site Infections (SSI): With an aging population, increased numbers of elderly patients are undergoing surgery. While surgical site infections negatively impact all patients, this is especially true in older patients. Approximately 11% of all nosocomial infections can be attributed to surgical site infections in this age group with this number anticipated to grow as the population ages.

Studies have indicated an increased length of stay by 2 weeks, doubling of hospital costs, significant loss in functional status, and a three to five times greater mortality associated with surgical site infections. When the infection is due to methicillin-resistant Staphylococcus aureus risk of death increases 11 fold. Independent predictors have been identified to help with risk stratification for SSI. They include comorbid conditions of COPD and obesity, wound class, and financial factors. No significant association for increased risk of surgical site infection was found with perioperative hyperglycemia, unlike the adult population at large. Unfortunately, appropriate perioperative antibiotic prophylaxis did not lower the risk of surgical site infection. Furthermore, no randomized controlled trials or targeted intervention studies have been completed based on the defined risk factors limiting overall key conclusions.

8) Influenza diagnosis: In data from one prospective review, the criteria of cough, fever greater than 38 degrees Celsius, and illness for less than 7 days increased the likelihood of influenza infection from 9% in those not meeting the criteria to 47% in those with all three criteria during flu season. Diagnostic testing was similarly reliable with positive rapid antigen testing in only 50% of culture positive patients. Interestingly, high fever was seen even in this older population where immunonsenescence is commonly encountered, and fever may be lacking even in the presence of significant infections. If the above criteria are met in the inpatient setting infection control procedures should be implemented.

What are the consequences of ignoring key concepts related to infection control in geriatrics?

  • Increased nosocomial infections

  • Increased antibiotic resistance

  • Increased length of hospitalization, cost and mortality

  • Increased C difficile infection rates

  • Increased MRSA infection and colonization rates

  • Increased falls

  • Increased fractures

  • More delirium

  • More ADRs (Adverse Drug Reactions)

  • More prolonged functional impairment after acute care episodes

  • Decreased quality of care and patient satisfaction in hospitalised elderly patients

  • More frequent hospital readmissions

What other information supports the conclusions of recent studies?

The key themes in all studies of inpatient geriatric units include a focus on improving functional status, mobilizing patients as early as possible, and minimizing the many risks associated with hospitalization. This requires a specific focus each day for the team managing the patient, simply asking, what are we doing today to get them up and out of the bed? Despite the best of intentions this agenda often falls prey to other competing demands and schedules. Along with recommendations for minimizing the number of foreign bodies in the patient (IV lines, endotracheal tubes, urinary catheters), key strategies include multi-component efforts to prevent or modulate delirium, and reducing polypharmacy and inappropriately chosen or dosed drugs and combinations of interacting drugs. Impaired mental status and reduced mobility clearly pre-dispose to infections of the skin, urinary tract, lungs and bloodstream. A patient who is more mobile, more alert, and eating well is less likely to become infected. Iatrogenic Infections are one of the most dangerous consequences of inpatient care for older patients, and mobilizing the patient is a key aspect of preventing those infections.

Summary of current controversies.

When examining the evidence used to formulate guidelines for infection prevention and control in older individuals, many of the available review articles lack good methodologic quality or clinical applicability. Published reviews look at common infections in the elderly population, specifically upper respiratory infections and urinary tract infections. There are very few randomized controlled trials to help define evidence-based guidelines. Furthermore, no systematic reviews examining Geriatric Inpatient units are very limited. In addition, a quality assessment of review articles in hospitalized elders on urinary and respiratory tract infections suggest poor methodological quality or lack clinical applicability. For example, only 3 of 51 articles reviewed described the source of the data used in the review. These findings underscore the need for better data to support evidence based practice guidelines in this specific patient population regardless of location in the hospital.

What is the impact of infection control in the geriatrics unit relative to the impact of other aspects of infection control?

Given the limited amount of research completed in the area of infection control, the Geriatric Unit per se has little proven impact in infection control. See earlier comments regarding overall improvement in “whole person” care that is believed to be potentially reduce infections.

Overview of important clinical trials, meta-analyses, case control studies, case series, and individual case reports related to infection control and the geriatrics unit.

There are insufficient data specific to infection control in geriatric care units to create meaningful tables. Leff et al in their 2005 study of Hospital at Home noted many fewer urinary or infectious complications in the experimental group patients compared with those receiving usual care at the hospital, but the sample was too small to reach significance. Counsell et al reported the most thoroughgoing prospective trial of Acute Care of the Elderly (ACE) inpatient units, taking a comprehensive geriatric approach to care planning between 1994 and 1997. Although measures were taken to reduce infectious complications, there was little comment on infections and infectious complications and the primary outcome was functional status. There was improved patient satisfaction for both patients and providers.

Controversies in detail.

1. When reviewing the benefits of acute care interventions for elderly populations, one study published in 2005 (Leff) suggests that the safest and most cost effective place to treat this frail population may be at home. This prospective study looked at a target sample of patients, 65 years of age and older, with pneumonia, CHF or COPD exacerbation, or cellulitis, enrolled in a hospital-at-home intervention, and compared them to a similar group observed in an inpatient acute care setting. Study findings showed decrease in nosocomial infections, delirium, restraints, sedative use and other complications that often occur in the hospitalized elder. Furthermore the overall cost of care was less for those treated at home.

2. Further controversy is raised over the benefits of transferring long-term care residents found to have a variety of infections to acute inpatient care settings. Three separate studies report the benefits of NOT hospitalizing frail elders who live in nursing home settings found to have pneumonia or other infections including cellulitis and genitourinary infections. One study specifically showed evidence that when compared to residents transferred to an acute care setting; those residents that were treated at a long-term care facility had an improved mortality rate and functional status 2 months following the acute illness.

What national and international guidelines exist related to infection control for geriatric patients?

While the American Geriatrics Society, an active national organization focused on geriatrics and geriatric care, has put forth several different guidelines on a range of issues, none exist addressing Geriatric Inpatient Units specifically. Several policies and guidelines on management of pain, prevention of functional decline, and reduction of delirium are worth noting.

What other consensus group statements exist, and what do key leaders advise?

The CDC and CMS (Center for Medicare and Medicaid) have developed regulatory guidelines for infection prevention and control in the Long Term Care Setting. These guidelines are based on CDC recommendations, information put forth by the Healthcare Infection Control Practice Advisory. There are no consensus statements specifically for Geriatric Inpatient Units.


Current Contributions and Key Conclusions:

Schneider, EL. “Infectious Disease in the Elderly”. Ann Intern Med. vol. 98. 1983. pp. 395-400.

Sjogren, P. “A Systematic Review of Preventive Effect of Oral Hygiene on Pneumonia and Respiratory Tract Infection in Elderly People in Hospitals and Nursing Homes: Effect Estimates and Methodolgical Quality of Randomized Controlled Trials”. J Am Geriatr Soc. vol. 56. 2008. pp. 2124-2130.

Woodford, HJ, George, J. “Diagnosis and Management of Urinary Tract Infections in Hospitalized Older People”. J Am Geriatr Soc. vol. 57. 2009. pp. 107-114.

Kaye, KS. “The Effect of Surgical Site Infection on Older Operative Pateints”. J Am Geriatr Soc. vol. 57. 2009. pp. 46-54.

Kaye, KS. “Risk Factors for Surgical Site Infections in Older People”. J Am Geriatr Soc. vol. 54. 2006. pp. 391-396.

Abrutyn, E. “Does Asymptomatic Bacteriuria Predict Mortality and Does Antimicrobial Treatment Reduce Mortality in Elderly Ambulatory Women”. Ann Intern Med. vol. 120. 1994. pp. 827-833.

McGarry, SA. “Surgical-Site Infection Due to Staphylococcus Aureus Among Eldelry Patients: Mortality, Duration of Hospitalization, and Cost”. Infect Control Hosp Epidemiol. vol. 25. 2004. pp. 461-467.

Walsh. “Clinical Features on Influenza A Virus in Older Hospitalized Persons”. J Am Geriatr Soc. vol. 50. 2002. pp. 1498-1503.

Nicole, LE. “IDSA of America for Diagnosis and Treatment of Asymptomatic Bacturia”. Clin Infect Dis. vol. 40. 2004. pp. 643-654.

“National Guideline Clearinghouse (NGC). Guideline synthesis: Diagnosis and management of uncomplicated lower urinary tract infection”. National Guideline Clearinghouse (NGC) [Web site]. 2008 Jan.

Shapey, SK. “activity of a dry mist hydrogen peroxide system against environmental Clostridium difficile contamination in elderly care wards”. Journal of Hospital Infection. vol. 70. 2008. pp. 136-141.

McNulty. “Successful Control of Clostridium Difficile infection in an elderly care unit though the use of a restrictive antibiotic policy”. Journal of Antimicrobial Chemotherapy. vol. 40. 1997. pp. 707-711.

Stelfox, HT. “Safety of patients isolated for infection control”. JAMA. vol. 290. 2003. pp. 1899-1905.

Wald, HE, Ma, A, Bratzler, DW, Kramer, AM. “Indwelling urinary catheter use in the post-operative period: analysis of the Nationakl Surgical Infection Precention Project data”. Arch Surg. vol. 143. 2008. pp. 551-557.

Bruminhent, J, Keegan, M, Lakhani, A, Roberts, IM, Paasalacqua, J. “Effectiveness of a simple intervention for prevention of catheter-associated urinary tract infections in a community teaching hospital”. Am J Infect Control. vol. 38. 2010. pp. 689-693.

Elpern, EH, Killeen, K, Ketchem, A, Wiley, A, Patel, G, Lateef, O. “Reducing use of urinary catheters and associated urinary tract infections”. Am J Crit Care. vol. 1. 2009. pp. 535-541.

Loeb, M, Hunt, D, O’Halloran, K, Carusone, SC, Dafoe, N, Walter, SD. “Stop orders to reduce inappropriate unnary catheterization in hospitalist patients: a randomized controlled clinical trial”. J Gen Intern Med. vol. 23. 2008. pp. 816-820.

Meddings, J, Rogers, MAM, Macy, M, Saint, S. “Systematic review and meta-analysis: reminder systems to reduce catheter-associated urinary tract infections and catheter use in hospitalized patients”. Clin Infect Dis. vol. 51. 2010. pp. 550-560.

Impacts of Geriatric Units:

Vogt, N, Lutters, M. “What's the Basis for Treating Infections Your Way? Quality Assessment of Review Articles on the Treatment of Urinary and Respiratory Tract Infections in Older People”. J Am Geriatr Soc. vol. 48. 2000. pp. 1454-1461.

Counsell, SR, Holder, CM, Liebenauer, LL, Palmer, RM, Fortinsky, RH, Kresevic, DM, Quinn, LM, Allen, KR, Covinsky, KE, Landefeld, CS. “Effects og a multicomponent intervention on functional outcomes and process of care in hospitalized older patients: a randomized controlled trial of Acute Care for Elders (ACE) in a community hospital”. J Am Geriatr Soc. vol. 48. 2000. pp. 1572-1581.

Controversies Related to Geriatric Units:

Leff, B. “Hospital at Home: Feasibility and Outcomes of a Program to Provide Hospital-Level Care at Home for acutely Ill Older Patients”. Ann Intern Med. vol. 143. 2005. pp. 798-808.

Boockvar, KS. “Medicare Expenditures for Nursing Home Residents Triaged to Nursing Home or Hospital for Acute Infection”. J Am Geriatr Soc. vol. 56. 2008. pp. 1206-1212.

Fried, TR. “Short-Term Functional Outcomes of Long-Term Care Residents with Pneumonia Treated with and without Hospital Transfer”. J Am Geriatr Soc. vol. 45. 1997. pp. 302-306.

Boockvar, KS. “Outcomes of Infection in Nursing Home Residents with and without Early Hospital Transfer”. J Am Geriatr Soc. vol. 53. 2005. pp. 590-596.