Risk of pneumonia in new users of cholinesterase inhibitors for dementia.
OBJECTIVE
To compare the risk of pneumonia in older adults receiving donepezil, galantamine, or rivastigmine for dementia.


METHODS
Retrospective cohort study.


METHODS
Nationally representative 5% sample of Medicare databases.


METHODS
Medicare beneficiaries aged 65 and older who newly initiated cholinesterase inhibitor therapy between 2006 and 2009.


METHODS
Pneumonia, defined as the presence of a diagnosis code for pneumonia as the primary diagnosis on an inpatient claim or on an emergency department claim followed by dispensing of appropriate antibiotics. Cox proportional hazards models were used to estimate the risk of pneumonia. Subgroup analyses and sensitivity analyses were conducted using alternative pneumonia definitions and adjustments using high-dimensional propensity scores to test the robustness of the results.


RESULTS
The mean age of 35,570 new users of cholinesterase inhibitors (30,174 users of donepezil, 1,176 users of galantamine, 4,220 users of rivastigmine) was 82; 75% were women, and 82% were white. The cumulative incidence of pneumonia was 51.9 per 1,000 person-years. The risk of pneumonia for rivastigmine users was 24% lower than that of donepezil users (hazard ratio (HR)=0.75, 95% confidence interval (CI)=0.60-0.93). Risk in galantamine users (HR=0.87, 95% CI=0.62-1.23) was not significantly different from risk in donepezil users. Results of subgroup and sensitivity analyses were similar to the primary results.


CONCLUSIONS
The risk of pneumonia was lower in individuals receiving rivastigmine than in those receiving donepezil. Additional studies are needed to confirm the findings of pneumonia risk between the oral and transdermal forms of rivastigmine and in users of galantamine.
Duke Clinical Research Institute, School of Medicine, Duke University, Durham, North Carolina.|School of Pharmacy and Institute of Clinical Pharmacy and Pharmaceutical Sciences, National Cheng Kung University, Tainan, Taiwan.
Edward Chia-Cheng
EC
Lai
Geriatric Medicine Unit, Massachusetts General Hospital, Boston, Massachusetts.
Monera B
MB
Wong
Health Outcome Research Center, National Cheng Kung University, Tainan, Taiwan.|Division of Geriatric Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
Isao
I
Iwata
Duke Clinical Research Institute, School of Medicine, Duke University, Durham, North Carolina.
Yinghong
Y
Zhang
School of Pharmacy and Institute of Clinical Pharmacy and Pharmaceutical Sciences, National Cheng Kung University, Tainan, Taiwan.|Department of Neurology, Tainan Sin-Lau Hospital, Tainan, Taiwan.
Cheng-Yang
CY
Hsieh
School of Pharmacy and Institute of Clinical Pharmacy and Pharmaceutical Sciences, National Cheng Kung University, Tainan, Taiwan.|Health Outcome Research Center, National Cheng Kung University, Tainan, Taiwan.
Yea-Huei
YH
Kao Yang
Duke Clinical Research Institute, School of Medicine, Duke University, Durham, North Carolina.|Department of Medicine, School of Medicine, Duke University, Durham, North Carolina.
Soko
S
Setoguchi
D000368:Aged; D000369:Aged, 80 and over; D002800:Cholinesterase Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D015331:Cohort Studies; D003704:Dementia / Q000188:drug therapy*; D000077265:Donepezil; D005260:Female; D005702:Galantamine / Q000009:adverse effects*; D006801:Humans; D007189:Indans / Q000009:adverse effects*; D008297:Male; D048448:Phenylcarbamates / Q000009:adverse effects*; D010880:Piperidines / Q000009:adverse effects*; D011014:Pneumonia / Q000139:chemically induced* / Q000453:epidemiology*; D012189:Retrospective Studies; D018570:Risk Assessment; D000068836:Rivastigmine
D002800:Cholinesterase Inhibitors; D007189:Indans; D048448:Phenylcarbamates; D010880:Piperidines; D005702:Galantamine; D000077265:Donepezil; D000068836:Rivastigmine
Medicare; cholinesterase inhibitors; cohort studies; dementia; pneumonia