EAL

UWL: Association With Outcomes (2009)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To assess whether the severity of dementia is related to unfavorable outcomes of nursing home-acquired pneumonia and how this relationship is mediated.

Inclusion Criteria:

Psychogeriatric disease (dementia syndrome: Alzheimer's disease, vascular dementia and mixed dementia)
Residing in the nursing home for at least four weeks
Pneumonia, as judged by the attending nursing home physician
Patients in whom antibiotic treatment was started.

Exclusion Criteria:

Cases in which the physician changed the diagnosis within 10 days (N=33)
Patients included from March 1997 until the end of data collection.

Description of Study Protocol:

Recruitment

This work is part of the Pneumonia Study, a prospective observational cohort study on the clinical course of pneumonia in psychogeriatric wards of 61 nursing homes in the Netherlands
706 consecutive patients with pneumonia were identified between October 1996 and July 1998.

Design

Prospective cohort study.

Statistical Analysis

Using univariate and multivariate analyses, the direct relationship between dementia severity and death rate, cure rate and increase in discomfort during pneumonia was considered
The relationship of dementia severity to the intermediate factors (swallowing disturbance, aspiration, adequacy of food intake, weight loss and dehydration) was assessed
The relationship between the intermediate factors to the outcomes was assessed
Cox proportional hazards analyses were used for two outcomes: Death rate within one week and cure rate within two weeks
Multiple logistic regression was used for the outcome death within three months
Multiple linear regression was used for the outcome increase in discomfort after three days, compared with two weeks before the treatment decision
Hazard rate ratios and odds ratios were determined from regression coefficients in proportional hazards and logistic regression. 95% confidence intervals were also calculated.
Tested for interactions between dementia severity and each intermediate factor and between dementia severity and type of dementia
Non-parametric paired tests were used to compare discomfort levels before and after the treatment decisions.

Data Collection Summary:

Timing of Measurements

Each patient was followed for three months, during which the nursing home physician monitored incident cure and death.

Dependent Variables

Death rate
Cure rate
Increase in discomfort at the onset of pneumonia, based on the nine-item observational Discomfort Scale; Dementia of Alzheimer Type
Nursing home physicians completed questionnaires about patients' condition at the time of treatment decision and twh weeks before, as well as a follow-up assessment performed three days after the baseline evaluation

Independent Variables

Dementia severity was measured by the Bedford Alzheimer Nursing Severity Scale
Related mediators: Swallowing disturbance, aspiration, insufficient food intake, weight loss and dehydration.

Control Variables

Age
Sex
Comorbid disease
Treatment characteristics.

Description of Actual Data Sample:

Initial N: 706 consecutive patients with pneumonia were identified
Attrition (final N): After application of inclusion and exclusion criteria, 374 demented patients treated with antibiotics for pneumonia were included in the analysis, 39% of them male
Age: Mean, 83.9±7.8 years (range, 41 to 103 years)
Ethnicity: Not mentioned: Authors note there are few non-Caucasians in Dutch nursing homes
Location: The Netherlands.

Summary of Results:

Relationship Between Possible Intermediate Factors and Death Rate Within 1 Week and Death Within 3 Months

Variables		Associations with Mortality [Adjusted HRR or OR (95% CI)]
Death Rate Within 1 Week (HRR)	Swallowing disturbance	1.2 (0.6, 2.5)
	Aspiration	0.9 (0.6, 1.3) per point increase
	Insufficient food intake	1.5 (1.0, 2.4) per point increase, P=0.06
	Weight loss	1.5 (0.8, 2.6)
	Dehydration	1.8 (1.2, 2.9) per point increase
Death Within 3 Months (OR)	Swallowing disturbance	1.6 (0.9, 3.0)
	Aspiration	1.4 (1.0, 2.0) per point increase, P=0.06
	Insufficient food intake	1.8 (1.2, 2.7) per point increase
	Weight loss	1.7 (1.0, 2.8), P<0.05
	Dehydration	1.5 (1.0, 2.3) per point increase, P=0.05

Other Findings

Most of the 374 patients recovered from pneumonia: 58% of them were cured within two weeks and 72% within the three-month follow-up
Within the first week, 17% of the patients died and 41% had died at the conclusion of three months
Dementia severity was independently related to death rate within the first week after pneumonia (hazard rate ratio, 3.0 for the most severely demented quartile vs. the least demented quartile; 95% confidence interval, 1.1-8.3) and to three-month mortality (odds ratio, 2.5; 95% confidence interval, 1.1-5.4)
The latter relation was in part mediated by aspiration and weight loss (odds ratio of dementia severity adjusted for these mediators declined from 2.5 to 1.9; 95% confidence interval, 0.8-4.3)
Dementia severity was not related to the cure rate within two weeks nor to an increase in discomfort after three days, compared with before the pneumonia

Author Conclusion:

The functional and pathophysiological consequences of progressive dementia account in part for increased three-month mortality after pneumonia
Mid-term mortality is expected to be high only in the most severely demented patients and in less severely demented patients who aspirated or who lost weight
Implications for end-of-life decision-making and effectiveness of preventive and curative interventions are discussed.

Funding Source:

Government:	Dutch Ministry of Public Health, Welfare and Sports
Other:	Society 'Het Zonnehuis'

Reviewer Comments:

Patients only followed for three months. Authors note the following limitations:

Assessments typical of usual daily care may lack accuracy
Effect of dementia severity
Association between dementia severity and incidence of pneumonia
Diagnosis of pneumonia may not have been accurate in all patients
Initiation of antibiotics was not standardized
Cognitive impairment was not measured.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	N/A
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	N/A

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
3.	Were study groups comparable?		N/A
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	N/A
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	N/A
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	Yes
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		???
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	???
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	N/A
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		???
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	???
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	???
	7.5.	Was the measurement of effect at an appropriate level of precision?	???
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	N/A
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes