JAMDA
Volume 12, Issue 1 , Pages 33-37, January 2011

Diabetes Mellitus, Glycemic Control, and Pneumonia in Long-Term Care Facilities: A 2-Year, Prospective Cohort Study

  • Liang-Kung Chen, MD

      Affiliations

    • Division of Geriatric Medicine, Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
    • Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan
    • National Yang Ming University School of Medicine, Taipei, Taiwan
    • ,
  • Li-Ning Peng, MD

      Affiliations

    • Division of Geriatric Medicine, Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
    • Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan
    • National Yang Ming University School of Medicine, Taipei, Taiwan
    • ,
  • Ming-Hsien Lin, MD

      Affiliations

    • Division of Geriatric Medicine, Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
    • Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan
    • National Yang Ming University School of Medicine, Taipei, Taiwan
    • ,
  • Hsiu-Yun Lai, MD

      Affiliations

    • Division of Geriatric Medicine, Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
    • Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan
    • National Yang Ming University School of Medicine, Taipei, Taiwan
    • ,
  • Hsin-Chieh Lin, RN

      Affiliations

    • National Taipei College of Nursing, Taipei, Taiwan
    • ,
  • Shinn-Jang Hwang, MD

      Affiliations

    • Division of Geriatric Medicine, Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
    • Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan
    • National Yang Ming University School of Medicine, Taipei, Taiwan
    • Corresponding Author InformationAddress correspondence to Shinn-Jang Hwang, MD, Department of Family Medicine, Taipei Veterans General Hospital, No. 201, Shih-Pai Road Section 2, Taipei, Taiwan 11217.

published online 09 August 2010.

Article Outline

Objective

To determine the relationships among diabetes mellitus (DM), glycemic control, and long-term care facility (LTCF)–acquired pneumonia.

Design

Prospective cohort study.

Setting

Ten private LTCFs in Taiwan.

Participants

Participants were 233 LTCF residents.

Measurements

Barthel index (BI), Charlson comorbidity index (CCI), hemoglobin A1c, episodes of LTCF-acquired pneumonia.

Intervention

None.

Results

A total of 233 residents (76.9 ± 10.6 years, 54.9% males, 27.9% diabetic) from 10 private LTCFs participated. There were 173 LTCF-acquired pneumonia episodes. The incidence of LTCF-acquired pneumonia between patients with and without diabetes, or between diabetic subjects with different status of glycemic control was similar. Adjusted for baseline BI, CCI, feeding tube placement, and baseline serum albumin, DM was not a significant risk factor for LTCF-acquired pneumonia. Poorer glycemic control (HbA1c >7%) was not a significant risk factor for LTCF-acquired pneumonia in diabetic subjects.

Conclusions

Tighter glycemic control did not protect diabetic LTCF residents from pneumonia. A prospective randomized controlled trial is needed to determine the optimal goal of glycemic control for LTCF residents.

Keywords: Diabetes mellitus, elderly, long-term care, nursing home

 

Diabetes mellitus (DM) is a common disorder in the elderly, and its prevalence may reach 20.0%–26.7% in long-term care facilities (LTCFs).1, 2 Compared with community-living elderly, LTCF residents are more likely to be diabetic, and they are more prone to develop DM-related, end-organ complications.3 Despite the high prevalence of DM in LTCFs, the management of DM among older diabetic LTCF residents is extremely difficult because of many factors, including physical disabilities, cognitive impairment, tube feeding, and inability to communicate with caregivers. This difficulty in management may be partly illustrated by studies on the dietary management of DM in LTCFs; the diabetic diet did not improve glycemic control,4 but may have increased the probability of protein-energy malnutrition among diabetic LTCF residents.5 It is generally agreed that glycemic control in frail older people with DM should be more conservative, and it has been suggested that the target for the glycosylated hemoglobin A1c (HbA1c) should be 8%.6 However, evidence supporting this conservative attitude toward diabetes care in frail older people is not available.

Optimal glycemic control is associated with better quality of life, better general health, better cognitive functioning, better sleep, less depression, and enhanced vitality in otherwise healthy diabetic older people,7 but the risk of tight glycemic control may outweigh the benefits in terms of improving quality of life among LTCF residents.8 Our previous work has shown that tight glycemic control in LTCFs is associated with a higher chance of developing hypoglycemia and a poorer functional status.9 However, determining the optimal target of glycemic control for LTCF residents should be balanced by many factors, such as quality of life, relief of hyper- and hypoglycemic symptoms, DM-related complications (eg, infections), and so on. A recent study has shown that a policy for DM treatment algorithm in LTCFs is not universally available,10 and the inconsistence of clinical practice with current management recommendations is common.11 Therefore, the main purpose of this study was to evaluate the relationships among DM, glycemic control, and LTCF-acquired pneumonia to provide information to establish evidence-based, practice guidance in the long-term care setting.

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Methods 

Study Subjects 

In 2005, there were 1003 registered LTCFs (total bed number, 43,653) in Taiwan, and more than 80% of these LTCFs were small (bed number <50) and belonged to the private sector. In 2006, all LTCFs with a bed number between 20 and 50 in northern Taipei City were invited to participate in the study, and residents were enrolled when the LTCF managers and residents' families agreed to participate. For every participant, LTCF chart records were reviewed in detail, including the past medical history on admission to the LTCF. Physical functional status (measured by the 100-point Barthel index) was evaluated by the research staff. The Charlson comorbidity index (CCI) was used to evaluate comorbidity.12 The study started in January of 2006 and continued until July of 2008. During the study period, all newly admitted residents in participating LTCFs were also screened for enrollment after their or their families' consent.

Follow-up 

Once enrolled, all participants and their personal care records in the LTCFs were reviewed by the research staff, and all participants were followed clinically for 2 years. For all participants, the total number of episodes of LTCF-acquired pneumonia and the date of the first episode were recorded. The incidence of LTCF-acquired pneumonia was then calculated as episodes per 1000 bed-days.

Diagnosis of Diabetes Mellitus 

The diagnosis of DM was determined by the chart records in the LTCFs. For every participant, DM status was reevaluated before the study according to the American Diabetes Association criteria.13 For every participant, HbA1c was tested at 3- to 6-month intervals.

Diagnosis of LTCF-acquired Pneumonia 

For every participant during the study period, all new-onset respiratory symptoms were evaluated by onsite nursing staff. Subjects were diagnosed as having LTCF-acquired pneumonia if 2 or more of the following symptoms and signs were present: (1) new or worse cough; (2) newly purulent sputum; (3) temperature of 38.1 °C or 1.1 °C more than the baseline; (4) respiratory rate more than 25 breaths per minute; (5) tachycardia; (6) new or worse hypoxia; (7) pleuritic chest pain; (8) decline in cognitive or functional status; and (9) physical findings on chest examination such as rales or rhonchi.14

Statistical Analysis 

Continuous variables in the text and tables are expressed as means ± standard deviation, and categorical data are expressed as percentages. Comparisons of continuous variables were done using Student t test, and comparisons of categorical variables were done using the chi-square test or Fisher's exact test. A Cox proportional hazards regression model was used to evaluate the relationships among the occurrence of probable pneumonia, DM, and glycemic control. A P value less than .05 (2-tailed) was considered statistically significant.

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Results 

Demography 

From January 2006 to July 2008, 233 residents (76.9 ± 10.6 years, 54.9% males) from 10 private LTCFs participated in the study. The common underlying diagnoses of the participants included hypertension (120/233, 51.5%), cerebrovascular disease (113/233, 48.5%), dementia (71/233, 30.5%), and DM (65/233, 27.9%). Overall, the mean Barthel index of all participants was 28.3 ± 32.1, and 77.3% (180/233) of the participants were completely bedridden. Meanwhile, 48.9% (114/233) of the patients were on long-term tube feeding, and 23.2% (54/233) had long-term, indwelling, urinary catheters.

Status of Diabetes Mellitus and Glycemic Control 

The overall prevalence of DM was 27.9%. Baseline demographic characteristics were similar between diabetic and nondiabetic participants, except that diabetic subjects included more females (55.4% versus 41.1%, P = .049) and had higher CCIs (3.5 ± 1.1 versus 2.2 ± 1.1, P < .001) (Table 1). The mean HbA1c of all diabetic subjects was 7.1% ± 0.9%, and 61.5% (40/65) of subjects had a mean HbA1c greater than 7.0%. Table 2 shows that subjects with LTCF-acquired pneumonia had a significantly lower Barthel index (16.7 ± 25.3 versus 33.3 ± 33.6, P < .001), CCI (2.9 ± 1.3 versus 2.4 ± 1.2, P = .012) and serum albumin levels (3.89 ± 0.3 versus 4.0 ± 0.37 mg/dL, P = .026) (Table 2). However, none of those factors were an independent risk factor for LTCF-acquired pneumonia on multiple logistic regression analysis (P all > .05).

Table 1. Comparisons of Demographic Characteristics between Subjects With and Without Diabetes Mellitus
Diabetic (n = 65)Nondiabetic (n = 168)P
Age, y75.0 ± 10.077.7 ± 10.7.073
Sex, % male44.658.9.049∗
Barthel index26.7 ± 31.028.9 ± 32.6.636
Charlson comorbidity index3.5 ± 1.12.2 ± 1.1<.001∗
Incidence of long-term care facility–acquired pneumonia (per 1000 bed-days)2.22.0.169
Serum markers of nutritional status
Hemoglobin (g/L)12.3 ± 1.712.7 ± 2.0.191
Serum albumin (mg/dL)4.0 ± 0.44.0 ± 0.4.781
Serum total cholesterol (mg/dL)175.7 ± 37.8173.5 ± 32.7.735

∗P < .05.

Table 2. Comparisons between Subjects With and Without Long-Term Care Facility–Acquired Pneumonia
Pneumonia (+) (n = 71)Pneumonia (–) (n = 162)P
Age, y77.3 ± 12.476.8 ± 9.7.732
Sex, % male52.156.2.566
Diabetes mellitus, %33.825.3.121
Barthel index16.7 ± 25.333.3 ± 33.6<.001∗
Charlson comorbidity index2.9 ± 1.32.4 ± 1.2.012∗
Serum markers of nutritional status
Hemoglobin (g/L)12.6 ± 1.812.7 ± 2.0.687
Serum albumin (mg/dL)3.9 ± 0.44.0 ± 0.4.026∗
Serum total cholesterol (mg/dL)172.0 ± 33.6175.3 ± 34.5.555

∗P < .05.

LTCF-acquired Pneumonia and DM 

During the study period, 173 episodes of LTCF-acquired pneumonia were identified, equaling 1.02 episodes per 1000 bed-days. Diabetic subjects were at a slightly higher risk of developing LTCF-acquired pneumonia than nondiabetic subjects, but this difference was not statistically significant (1.12 versus 0.98 episodes per 1000 bed-days, P = .169). The incidence of LTCF-acquired pneumonia among diabetic subjects with different degrees of glycemic control was similar (HbA1c >7% versus HbA1c ≤7%: 1.03 versus 1.26 episodes per 1000 bed-days, P = .158). Adjusted for baseline Barthel index, CCI, feeding tube placement, and baseline serum albumin, DM was not a significant risk factor for LTCF-acquired pneumonia in this study (hazard ratio [HR] = 1.30, 95% confidence interval [CI] = 0.68–2.48) (Figure 1). Moreover, poorer glycemic control (HbA1c >7%) was not a significant risk factor for LTCF-acquired pneumonia in diabetic subjects (HR = 1.16, 95% CI = 0.47–2.89) (Figure 2).

  • View full-size image.
  • Fig. 2 

    Relationship between glycemic control and time to first LTCF-acquired pneumonia among diabetic LTCF residents after adjustment of the Charleson comorbidity index.

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Discussion 

Determining the target of glycemic control in the elderly is a complex health care issue.15 LTCF residents are usually old, frail, disabled, cognitively impaired, or have limited communication ability, and they are at a particularly high risk for hypoglycemia.9 Although it is generally agreed that the target of glycemic control needs to be modified in the LTCF setting, the risk of suboptimal glycemic control among LTCF residents is always a concern, especially with respect to infections. Despite advances in the management of DM and infectious diseases, diabetic patients are still at an increased risk of infections.16 Common community-acquired infections of diabetic patients include soft tissue infections, respiratory infections, urinary tract infections, and periodontal disease.17 A large survey in the United Kingdom showed that diabetic patients were significantly more likely to consult general practitioners because of respiratory tract infections,18 and another population-based cohort study indicated that DM and poor long-term glycemic control both significantly increased the risk of hospitalization because of pneumonia.19 In addition, the adverse impact of DM on mortality and morbidity during influenza epidemics has been well recognized.20, 21 However, a recent systemic review has clearly indicated that intensive glucose control did reduce the risk for some cardiovascular outcomes, but not reduce the risk for cardiovascular death or all-cause mortality and increased the risk for severe hypoglycemia.22 Moreover, different classes of oral antidiabetes drugs are associated with different clinical outcomes,23 but it is still premature to evaluate the medication effect on clinical outcomes in this study. Nevertheless, further studies to evaluate the effect of different antihyperglycemic drugs in long-term care settings are of great importance.

In LTCFs, pneumonia is the leading cause of mortality24, 25 and morbidity,26, 27, 28, 29 and it is the main condition responsible for transfers of residents to acute care facilities.30, 31, 32 Although DM is a common disease in LTCFs, standards of glycemic control in this setting are not well based on evidence. This study cohort is different from common LTCF residents in the United States in that they are more severely disabled but less likely to be demented. The lower prevalence of dementia in this setting may be because of the different ethnic background as well as the underdiagnosis of dementia in this setting. Owing to the traditional concepts of filial piety in Taiwan, older people may not be taken to the LTCFs until they are severely disabled, which may explain the different demographic characteristics of this study cohort to common LTCF residents in the United States. Also, a high prevalence of feeding tube placement is also different from the United States. However, because most LTCF residents are severely disabled, the high prevalence of feeding tube placement may not be surprising. A previous national study also showed that feeding tube placement is common among LTCF residents in Taiwan.33 In this study, LTCF residents with a poorer Barthel index, higher CCI, and lower serum albumin level were more prone to develop LTCF-acquired pneumonia, although these factors and DM were not independent risk factors. Moreover, a mean HbA1c of 7% or lower did not significantly protect diabetic LTCF residents from pneumonia. Altogether, the study results imply that development of LTCF-acquired pneumonia is more likely to be related to the infection control strategy at the LTCFs, not the baseline demographic characteristics of the residents. To the best of our knowledge, no other report has clearly shown the relationships among DM, glycemic control, and LTCF-acquired pneumonia. Although it is generally agreed that glycemic control should be more conservative, evidence supporting this strategy is not well established. On the other hand, evidence supporting tight glycemic control in this setting is also lacking. Therefore, we believe these study results provide important information to facilitate an evidence-based strategy for diabetes care in long-term care settings.

This study had several limitations. First, only 233 residents from 10 private LTCFs participated in this study, and the differences in the demographic profiles between participating LTCFs and nonparticipating LTCFs were unclear. Although the study results may not sufficiently represent all LTCF residents in Taiwan, the results obtained from this study are important in providing evidence supporting the conservative attitude to glycemic control among LTCF residents. Second, the prospective, observational, study design limited the ability to determine the optimal level of HbA1c from this study. A prospective case-control study with stratified target HbA1c levels is needed to evaluate the most appropriate glycemic control in LTCFs. Third, pneumonia represents the most common and important infection in DM, but many other DM-related complications should also be considered to optimize the target HbA1c level in this setting. Fourth, owing to the lack of chest X-ray diagnosis in this study, febrile bronchitis may be another possible diagnosis other than pneumonia and the high prevalence of feeding tube placement also increased the possibility of aspiration pneumonia. However, the clinical effectiveness of the diagnostic criteria adopted in this study has been shown14 and feeding tube placement has been adjusted in the regression model showing no statistical significance.

In conclusion, the prevalence of DM was 27.9% in LTCFs in Taiwan and the incidence of LTCF-acquired pneumonia was 1.02 episodes per 1000 bed-days. Adjusted for baseline Barthel index, CCI, serum albumin level, and feeding tube placement, DM was not a significant risk factor for LTCF-acquired pneumonia. Moreover, a mean HbA1c of 7% or less did not prevent LTCF residents from LTCF-acquired pneumonia. A further prospective, interventional study is needed to determine the optimal HbA1c level in patients in LTCFs.

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 The authors have no conflicts of interest.

PII: S1525-8610(10)00036-8

doi:10.1016/j.jamda.2010.01.010

JAMDA
Volume 12, Issue 1 , Pages 33-37, January 2011

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