Are Older Women More Likely to Get
Inappropriate Drugs?
Arlene S. Bierman, MD, MS
Ontario Women’s Health Council Chair in Women’s Health
Centre for Research in Inner City Health
St. Michael’s Hospital
June 28, 2005
 Potentially Inappropriate Prescribing in the Elderly (PIPE)
Study
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1Center
Mary Jo V. Pugh PhD, RN 5,6
B. Graeme Fincke, MD 1,2
Amy Rosen, PhD 1,2
Fran Cunningham, PharmD 4
Bei-Hung Chang, ScD 1,2
Megan Amuan MPH 1
Muriel Burke, PharmD 4
Irfan Dalla 3
Dan Berlowitz, MD, MPH 1,2
for Health Quality, Outcomes and Economic Research, Bedford VA;
2 Boston University School of Public Health;
3 University of Toronto;
4 Pharmacy Benefits Management Strategic Healthcare Group, Hines VA and University
of Chicago, Illinois
5 Veterans Evidence-based Research, Dissemination, and Implementation Center,
6 South Texas Healthcare System, Audie L. Murphy Division, San Antonio, Texas;
University of Texas Health Science Center at San Antonio
Inappropriate Prescribing in the Elderly
 Prescribing of drugs for which potential harms
outweigh potential benefits is a major patient safety
concern in the elderly.
 Inappropriate prescribing increases risk for falls, hip
fractures, cognitive impairment, diminished
independence, and death.
 Studies consistently find that 20-27% of older
Americans receive drugs identified as inappropriate,
with little to no improvement in nearly two decades.
Gender Differences in Potentially
Inappropriate Prescribing
 Prior studies of community-dwelling elders have
suggested that older women were more likely to receive
potentially inappropriate drugs than men.
 No prior study has examined whether gender differences
in potentially appropriate use of these drugs could explain
this or the factors associated with gender differences
inappropriate prescribing.
 Examination of the patterns and correlates of these
gender differences can provide evidence to develop and
implement effective quality improvement interventions.
Study Objectives
 To assess gender differences in rates of
inappropriate prescribing
 To assess whether gender differences are
explained by gender differences in potentially
appropriate indications for these drugs.
 To examine gender differences in the correlates
of inappropriate drug use.
Methods:
Data Sources
 Multiple Linked US Veterans Administration
(VA) Data Sets
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Administrative Data: Demographics
Inpatient Records: Diagnoses and Utilization
Outpatient Records: Diagnoses and Utilization
National Ambulatory Pharmacy Data: Drugs, Dose,
Duration
– Veterans Health Survey: Race/Ethnicity
Study Population
 Cohort Identification
 At least one outpatient visit in Fiscal Year (FY)1999 and
FY 2000
 > 65 years of age October 1, 1999
Potentially Inappropriate Prescribing:
Beers Criteria
 Potentially Inappropriate Prescribing in the Elderly
(Beers, 1991,1997 update 2003).
– Explicit criteria, expert consensus panel
– 33 drugs considered inappropriate regardless of diagnosis
(disease-independent)
– dose limitations
– drug-drug/drug-disease interactions
 Controversial because clinicians argued that some drugs
may be appropriate for specific patients in certain
circumstances
Outcome Variable:
Diagnosis-Adjusted Inappropriate Prescribing
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AHRQ (US Agency for Healthcare and Quality)
expert consensus panel
- Grouped 33 Beers disease-independent drugs
into 3 categories using modified Delphi process;
Always-avoid
: 11 drugs
Rarely-appropriate
: 8 drugs
Some-indications: 14 drugs
Diagnosis-adjusted PIPE: Algorithms develop using
ICD-9 codes and pharmacy data to adjust for
potentially appropriate use.
Covariates:
Patient Characteristics
 Demographics
- Age, sex, race/ethnicity
- 1999 large Health Survey of Veterans provided missing race data
 Physical and Psychiatric Comorbidity
- Disease burden assessment by Selim’s physical and psychiatric
Comorbidity Index
- Assessed comorbidity status for 3 years (FY98-00)
• # psychiatric diagnoses
• # physical diagnoses
 Number of unique medications (FY 00)
Covariates
Characteristics of Care
 Type of Care Received (FY 99)
– Number of Primary Care Visits
– Number of Different Specialty Clinics
– Geriatric Care
– Long-term Care, Medical or Psychiatric Hospitalizations
 Outpatient visits used to assess continuity of care
number of outpatient visits in primary care (FY 99)
Total number of outpatient visits
Method - Analysis
 We determined the prevalence of any use of potentially
inappropriate drugs among men and women. Then, we used
the VA PIPE study algorithms to examine the proportion of this
use that may have been appropriate and whether the
proportion that remained inappropriate differed by gender.
 Using logistic regression we determined the unadjusted and
adjusted odds ratios of women receiving diagnosis-adjusted
inappropriate drugs compared to men both for individual agents
and by drug category (always avoid, rarely appropriate, and
rare indication). Patient and care characteristics were included
as covariates.
 Logistic regressions stratified by gender were conducted to
examine gender differences in factors associated with receipt
of inappropriate medications.
Gender Differences in Use of Inappropriate Drugs
Male (%)
(N=946,641)
Female (%)
(N=19,115)
OR
(F vs.M)
Always avoid
0.9
1.7
1.95
Rarely appropriate
10.5
12.4
1.31
Some indication
18.1
22.6
1.44
At least one drug
25.7
31.0
1.45
Parameter
All comparisons are significant with P< 0.0001
Gender Differences Proportion
Inappropriate – Some Indication
Drug
Proportion Inappropriate After Adjusting for
Diagnosis/Duration of Use (%)
Male
Female
Amitriptyline
75.0
76.1
Doxepin
81.6
80.2
Oxybutynin
74.8
52.6
Chlorpheniramine
92.1
93.1
Diphenhydramine
94.2
95.0
Odds of Receiving Inappropriate Drugs:
Diagnosis Adjusted
2.2
2.0
2
1.7
1.8
1.6
OR (F vs. M)
1.4
1.3
1.3
1.3
1.2
1.2
1.2
1.2
Unadjusted
1
Adjusted*
0.8
0.6
0.4
0.2
0
Any Inappropriate
Drug
Always Avoid
Rare Indication
Some Indicaton
*Adjusted for demographics, comorbidities, unique meds & characteristics of care
Gender Differences in Diagnosis-Adjusted
Use of Individual Agents: Always Avoid
Unadjusted
Drug
Adjusted*
OR
95% CI
OR
95% CI
Meperidine
1.7
1.2-2.5
1.5
1.1-2.2
Belladonna
Alkaloids
2.6
1.3-5.3
2.2
1.1-4.4
Dicyclomine
2.1
1.8-2.5
1.8
1.6-2.1
Hyoscyamine
2.5
2.0-3.2
2.5
1.9-3.1
Propantheline
3.2
2.1-4.7
2.7
1.8-4.0
*Adjusted for demographics, comorbidities, unique meds & characteristics of care
Gender Differences in Diagnosis-Adjusted
Use of Individual Agents: Rare Indication
Unadjusted
Adjusted*
OR
95% CI
OR
95% CI
Diazepam
1.2
1.1-1.4
1.0
0.9-1.1
Propoxyphene
1.3
1.3-1.4
1.2
1.1-1.3
Cyclobenzaprine
1.4
1.2-1.5
1.4
1.3-1.6
Methocarbamol
1.2
1.1-1.3
1.2
1.1-1.3
Drug
*Adjusted for demographics, comorbidities, unique meds & characteristics of care
Gender Differences in Diagnosis-Adjusted
Use of Individual Agents: Some Indication
Unadjusted
Drug
Adjusted*
OR
95% CI
OR
95% CI
Amitriptyline
1.4
1.3-1.5
1.3
1.2-1.4
Doxepin
1.2
1.0-1.4
1.0
0.8-1.1
Disopyramide
4.0
1.6-9.9
3.0
1.2-7.4
Oxybutynin
2.0
1.9-2.2
1.8
1.6-1.9
Chlorpheniramine
1.4
1.3-1.5
1.3
1.2-1.4
Diphenhydramine
1.5
1.4-1.6
1.4
1.3-1.5
Promethazine
1.7
1.3-2.1
1.4
1.1-1.7
*Adjusted for demographics, comorbidities, unique meds & characteristics of care
Drugs less likely to be received by
women – Some Indication
Unadjusted
Drugs
Adjusted*
OR
95% CI
OR
95% CI
Indomethacin
0.6
0.5-0.7
0.6
0.5-0.7
Dipyridamole
0.8
0.6-1.0
0.7
0.5-0.8
Cyproheptadine
0.6
0.5-0.9
0.5
0.4-0.6
*Adjusted for demographics, comorbidities, unique meds & characteristics of care
Correlates of Inappropriate Prescribing
Male (N=834,251)
Female (N=15,903)
Parameter
OR
P-value
OR
P-Value
Hispanic
1.08
<0.00
1.36
0.03
1 mental health
diagnosis
1.32
<0.00
0.99
0.88
2 or more mental
health diagnosis
1.61
<0.00
1.08
0.20
Number of
medications
1.17
<0.00
1.18
<0.00
Geriatric visit
0.65
<0.00
0.64
<0.00
Age, continuity of care, long-term care, medical or psychiatric hospitalizations included
in model.
Conclusions
 Older women were more likely to receive inappropriate
medications than older men, even after accounting for a
liberal set of indications.
 Analgesic, psychotropic, and anticholinergic
medications that should be avoided contribute to higher
rates of inappropriate drug use among older women.
 Psychiatric comorbidity is a predictor of inappropriate
drug use in men but not in women.
Conclusions

Receipt of geriatric care was equally protective for
men and women, though only a small proportion of
the sample received this care.

Men and women did not differ in proportion of drugs
that were inappropriate, inappropriate dosing, or
duration.
Limitations
 While some use is classified as potentially appropriate
often safer or more effective options exist.
 Data may not capture all drugs received by the cohort,
as those who have other drug coverage may have
received medications outside the VA.
 VA population may limit generalizability.
 A recent update of the Beers criteria added additional
medications to the list of disease-independent drugs.
Implications
 Because of these differences studies on inappropriate
prescribing should examine gender differences when
possible.
 Efforts to improve the quality of medication
management in the elderly should address gender
differences in prescribing patterns.
 Improved access to geriatric care may decrease rates
of inappropriate prescribing.