Evaluating the prevalence of potentially inappropriate prescribing in older adults in intermediate care facilities: a cross-sectional observational study
Int J Clin Pharm
Evaluating the prevalence of potentially inappropriate prescribing in older adults in intermediate care facilities: a cross-sectional observational study
Anna Millar 0 1 2
Carmel Hughes 0 1 2
Crist´ın Ryan 0 1 2
0 School of Pharmacy, Royal College of Surgeons in Ireland , 123 St. Stephens Green, Dublin 2 , Ireland
1 School of Pharmacy, Queen's University Belfast , 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland , UK
2 & Anna Millar
Background Potentially inappropriate prescribing (PIP) [encompassing potentially inappropriate medicines (PIMs) and potential prescribing omissions (PPOs)], is prevalent amongst older adults in primary and secondary care. However, PIP prevalence in intermediate care (IC) is unknown. Objective To determine the prevalence of PIMs/ PPOs and associated patient factors. Setting Three IC facilities in Northern Ireland. Method The Screening Tool of Older People's Prescriptions and the Screening Tool to Alert doctors to Right Treatment were used to identify PIP over 8 weeks. Wilcoxon signed-rank tests were performed to compare the prevalence of PIMs/PPOs at admission and discharge. Spearman's correlation coefficients were calculated to determine factors associated with PIMs/PPOs (p 0.05 considered significant). Main outcome measure Prevalence of PIMs/ PPOs. Results 74 patients [mean age 83.5(±7.4) years] were included. Discharge medication data were available for 30 (40.5%) patients. 53 (71.6%) and 22 (73.3%) patients had C1 PIM at admission and discharge, respectively. 45 (60.8%) and 15 (50.0%) patients had C1 PPO at admission and discharge, respectively. No significant difference was found in PIM/PPO prevalence at admission compared to discharge (Z = -0.36, p = 0.72; Z = -1.63, p = 0.10). Increasing comorbidity and medication regimen complexity were associated with PIMs at admission (r = 0.265, p = 0.023; r = 0.338 p = 0.003). The number of medicines was correlated with PIMs at admission (r = 0.391, p = 0.001) and discharge (r = 0.515, p = 0.004). Conclusion Whilst IC represents an ideal setting in which to review prescribing, this study found PIP to be highly prevalent in older adults in IC, with no detectably significant change in prevalence between admission to and discharge from this setting.
Aged; Inappropriate prescribing; Intermediate care facilities; Northern Ireland; Potentially inappropriate medication list
Impacts on practice
Patients admitted to intermediate care facilities are
generally older adults, prescribed polypharmacy, who
had recently been discharged from hospital.
Potentially inappropriate prescribing is highly prevalent
amongst older adults in intermediate care and do not
change significantly between admission and discharge.
Intermediate care facilities provide an ideal setting in
which to review the appropriateness of patients’
prescriptions, however this study suggests that does
In the United Kingdom (UK), intermediate care (IC)
describes a range of services aimed at preventing
unnecessary hospitalisation, promoting faster recovery
from illness and maximising independence [
development of IC has been driven largely in response to
the increasing pressure faced by healthcare services as a
result of the ageing population. Although the term ‘IC’
has its origins in the UK, several similar healthcare
models exist elsewhere globally, including ‘sub-acute
care’, ‘post-acute care’ and ‘transition care’ [
However, previous work has highlighted several
inconsistencies between the concept of IC defined in the literature
and the day-to-day realities of such services, for example
the concept of IC preventing hospitalisation was not
found to represent the reality in practice [
Additionally, despite the importance placed on the concept of
multidisciplinary involvement in IC, the reality is that
pharmacists are not widely involved with IC, nor is
medicines management integral to IC services in
Northern Ireland (NI) [
]. Despite IC providing an
ideal setting for medication review, concerns regarding
the lack of responsibility for the review of patients’
medicines in IC has also been highlighted [
Potentially inappropriate prescribing (PIP),
encompassing potentially inappropriate medicines (PIMs) and the
omission of clinically indicated medicines, i.e. potential
prescribing omissions (PPOs), has received increasing
attention due to its association with avoidable adverse drug
events (ADEs) and hospitalisation amongst older adults
]. Increasing age, comorbidity and number of medicines
prescribed predispose individuals to PIP [
The Screening Tool of Older People’s Prescriptions
(STOPP) and the Screening Tool to Alert doctors to
Right Treatment (START) were developed to identify
instances of PIMs and PPOs, respectively [
in 2008, STOPP/START (version 1) have been applied
in numerous clinical settings to identify PIP in adults
aged C65 years. The criteria have been recently updated
]. STOPP/START version 2 now includes a total of
114 criteria, organised into 22 categories, representing a
31% increase in the number of criteria compared with
version 1. Whilst predominantly an explicit set of
criteria, STOPP version 2 also includes three implicit
criteria within a new category (‘indication of medication’)
which require clinical judgement in order to be applied
to a patient’s medicines [
PIP has been shown to be prevalent amongst older adults
in primary and secondary care settings, however, to the
authors’ knowledge, no previous investigation into the
prevalence of PIP in the IC setting has been conducted in
the UK. Elsewhere in Europe, Bakken et al. [
that the prevalence of inappropriate prescribing in IC
increased from 24% at admission to 35% at discharge, as
measured by the Norwegian General Practice (NORGEP)
criteria, an explicit list of medicines, medicine dosages,
and medicine combinations to be avoided in older adults
Patients were eligible for inclusion if they were:
Aged C65 years at admission; Admitted to an IC-bed (i.e. not receiving other categories of care often provided within such facilities e.g. palliative care);
Prescribed C1 regular (as opposed to ‘when required’)
Patients meeting the above criteria were included
consecutively over the 8-week period (August–October 2014).
A data collection form was developed to record data from
patients’ medical notes and prescription charts, including
the following demographic information:
Aim of the study
As little was known about the IC population and the
prevalence of PIP within it, the aim of the present study
was to prospectively determine the PIP prevalence amongst
older adults admitted to three IC facilities in NI over an
8-week period. The objectives of the study were to:
Describe the IC population, including patient
comorbidity, complexity of patients’ medication regimens
and changes made to patients’ medications from
admission to discharge
Determine the prevalence of PIMs and PPOs using
STOPP/START (version 2) at admission and discharge,
and whether these changed significantly between these
Determine which (if any) patient-related factors (age,
gender, comorbidity, medication regimen complexity,
number of prescribed medications at admission and
discharge) were associated with PIMs/PPOs.
Ethical approval was not required as the study was
conducted as a ‘service evaluation’ within the Health and
Social Care Trust governing the IC facilities. Approval for
the study was granted by the Trust’s Audit Committee.
Pre-IC location (e.g. hospital, home)
Reason for admission to IC
Where applicable, the date of discharge (to determine
length of stay) and destination post-discharge were collected.
Details of patients’ prescribed medicines, medical history and
biochemical data were recorded to apply STOPP/START. As
not all patients were discharged during the study, discharge
data were not available for the entire cohort.
Patient comorbidity was quantified using Charlson’s
Comorbidity Index (CCI) [
], a widely used tool in clinical
]. Prescribed medicines were categorised
according to the British National Formulary [
], a UK
reference source, which categorises medicines according to their
primary indication, e.g. ‘central nervous system (CNS)’ or
‘gastrointestinal system (GI)’. The complexity of patients’
medication regimens was quantified using the Medication
Regimen Complexity Index (MRCI) [
]. The MRCI is a
validated tool used to score a medication regimen based on the
number of medicines, formulations, dosing frequencies and
additional instructions (e.g. ‘take with food’) [
made to patients’ medication regimens between admission
and discharge were analysed descriptively as the number and
type of changes made. Instances of PIP were identified by
screening patients’ data collection forms against the full set of
STOPP/START criteria. Data collection and screening was
conducted by AM, a pharmacist experienced in the use of the
STOPP/START criteria. The prevalence of PIMs and PPOs
was defined as the percentage of patients with C1 PIM or C1
The Wilcoxon signed-rank test (Z) was performed to compare
the prevalence of PIMs and PPOs at admission and discharge.
Two-tailed bivariate correlations (Spearman’s rho correlation
coefficient) were calculated to establish the relationship
between the number of PIMs and PPOs at admission and
discharge with: age, gender, CCI, MRCI, number of
prescribed medications at admission and discharge. A probability
value of\0.05 was considered significant. Statistical analysis
was performed using Statistical Package for the Social
Sciences (SPSS) version 20.0.
admitted to IC from hospital. Rehabilitation following a
fall (with or without fracture) was the single most common
reason for admission to IC, accounting for 26 (35.1%)
admissions. Of the 74 admissions recorded, 38 (51.4%)
patients were discharged during the 8-week period and
three (4.1%) patients died (Table 1).
Patients were prescribed a mean of 10.4 (±3.8; range
3–19) regular medicines. Seventy-one (95.9%) patients
were prescribed polypharmacy (C4 medicines) [
admission. Data pertaining to medicines prescribed at
discharge were available for 30 (40.5%) patients, who were
prescribed a mean of 9.8 (±4.0; range 2–18) regular
A total of 30 patients’ medication data were collected
from admission to discharge and overall 120 changes were
made to these patients’ medication regimens during their
stay in IC. A mean of 4.0 (±2.7; range 0–9) changes were
made to patients’ medication regimens during their stay. Of
these, 50 (41.7%) were medications being discontinued, 45
(37.5%) were medicines being started and 25 (20.8%) were
‘other’ changes (dose/frequency/formulation alterations).
Prevalence of PIMs
STOPP identified 147 PIMs amongst 53 (71.6%) patients at
admission (range 0–8). Thirty-four (72.3%) females had
C1 PIM compared to 19 (70.4%) males. At discharge, 54
PIMs were identified amongst 22 (73.3%) patients (range
0–6). Seventeen (73.9%) females had C1 PIM compared to
5 (71.4%) males.
The 147 instances of PIMs at admission were
attributable to 122 medications. The number of PIMs was
greater than the number of associated medications as one
medicine can be considered potentially inappropriate under
C1 STOPP criteria. CNS medications accounted for the
majority of medications responsible for PIMs at admission
(50; 41.0%). The 54 instances of PIMs at discharge were
attributable to 53 medications. GI system medicines
accounted for the majority of medications responsible for
PIMs at discharge (21; 39.6%).
The STOPP category ‘indication of medication’ was
responsible for the majority of PIMs at both admission and
discharge. Within this category, the STOPP criterion ‘any
drug prescribed beyond the recommended duration’,
accounted for 14.3% of PIMs at admission and the STOPP
criterion ‘any duplicate drug class prescription’, accounted
for 16.7% of PIMs at discharge (Table 2).
Prevalence of PPOs
A total of 74 patients were included; 47 (63.5%) were
female. The mean age was 83.5 years (±7.4; range
66–102). The majority of patients (68; 91.9%) were
START identified 95 PPOs amongst 45 (60.8%) patients at
admission (range 0–6 per patient). Twenty-nine (61.7%)
females had C1 PPO compared to 16 (59.3%) males. At
Number of patient admissions n = 74 (%)
CCI Charlson Comorbidity index; MRCI medication regimen complexity index
discharge, 34 PPOs were identified amongst 15 (50.0%)
patients (range 0–6 per patient). Twelve (52.2%) females
had C1 PPO compared to 3 (42.9%) males.
At both time-points, the most frequently identified PPOs
related to the ‘musculoskeletal system’ START category,
which accounted for 60.0% of PPOs at admission and
55.9% of PPOs at discharge (Table 3). The most frequent
PPO at admission was ‘vitamin D supplement in older
people who are housebound or experiencing falls or with
osteopenia’ (20; 27.0%). The most frequent PPOs at
discharge were ‘vitamin D and calcium supplements in
patients with known osteoporosis’ (6; 17.6%), the omission
of ‘bone anti-resorptive therapy in patients with
documented osteoporosis’ (6; 17.6%), and ‘vitamin D
supplement in older people who are housebound or experiencing
falls or with osteopenia’ (6; 17.6%).
Change in prevalence of PIP between admission and discharge
No significant difference was found in the prevalence of
PIMs at admission (median 1.5; interquartile range (IQR)
3.0) compared to discharge (median 2.0; IQR 3.0),
Z = -0.36, p = 0.72. Similarly, no significant difference
was found between PPO prevalence at admission (median
1.0; IQR 2.0) and discharge (median 0.5; IQR 2.0)
Z = -1.63, p = 0.10.
Patient-related factors associated with PIP
Increasing age was negatively correlated with PPOs at
discharge (r = -0.436, p = 0.016). Increasing CCI was
associated with PIMs at admission (r = 0.265, p = 0.023), as was
increasing MRCI scores at admission (r = 0.338, p = 0.003).
Increasing number of prescribed medicines at admission was
associated with PIMs at both admission (r = 0.391,
p = 0.001) and discharge (r = 0.515, p = 0.004).
To our knowledge, this was the first study investigating
prescribing appropriateness amongst older adults in IC, in
the UK. The average age, mortality, comorbidity and
ACE Angiotensin converting enzyme; IHD ischaemic heart diseases; COPD chronic obstructive pulmonary disease; DMARD disease modifying
antirheumatic drug; PPO potential prescribing omission
polypharmacy reported in this cohort, demonstrates that IC
facilities cater to an older population in relatively poor
health. This provides further evidence to support
previously highlighted disparities between the concept of
IC and the realities of the service [
]. For one, the
conceptual role of IC in ‘preventing unnecessary
hospitalisation’ is not currently being realised, as only a
minority of patients were admitted to IC from their place of
Using STOPP [
], this study found that the prevalence
of PIMs amongst IC patients was 71.6% at admission and
73.3% at discharge. The majority of medicines responsible
for PIMs at admission and discharge were CNS and GI
medicines, respectively. The STOPP category ‘indication
of medicine’ accounted for the majority of PIMs at both
time-points. Notably, nearly one fifth of patients in this
cohort at admission were prescribed benzodiazepines for a
duration of more than 4 weeks. The use of benzodiazepines
in older adults has been associated with clinically
important ADEs including impaired cognition and falls [
Despite this, prescribing patterns of benzodiazepines are
often in conflict with prescribing recommendations [
Patients may be reluctant to discontinue certain PIMs,
including benzodiazepines, due to dependence associated
with these medicines [
]. Prescribers may also be hesitant
to discontinue medicines, particularly when initiated by
another prescriber [
Using START [
], this study found that 60.8 and 50.0%
of patients in the cohort had C1 clinically indicated
medicines omitted from their medication regimen without a
documented reason, at admission and discharge,
respectively. The START category ‘musculoskeletal’ accounted
for the majority of PPOs at both time-points. This category
encompasses the omission of vitamin D, calcium and bone
anti-resorptive agents, medicines of particular importance,
given the frailty of the population under investigation. The
reasons for their omission are unclear. However, such is the
nature of STOPP/START that there is greater opportunity
for the identification of PPOs amongst patients whose past
medical histories are documented comprehensively and
greater opportunity for the identification of PIMs amongst
patients who past medical histories lack detail.
The prevalence of PIMs and PPOs reported are similar
to those found in older adults in hospital [
] and higher
than those reported in primary care [
] and nursing homes
]. However, these studies used STOPP/START version
1, and so their findings cannot be compared directly with
those reported here. It is, nonetheless, possible that the
higher prevalence rates of PIMs/PPOs reported here,
compared with previous studies using STOPP/START is
due, in part, to the extension of criteria in the updated
], notably, the inclusion of the three new implicit
criteria under the category ‘indication of medication’:
Drug prescribed without evidence-based indication
Drug prescribed beyond recommended duration
Duplicate drug class prescription.
Despite patients’ medication regimens undergoing an
average of four changes, it was found that the prevalence of
PIP did not change significantly between admission and
discharge. Ideally, PIP prevalence should decrease during a
patient’s stay, as the rehabilitative IC environment provides
a (theoretically) ideal opportunity for the optimisation of
all aspects of patients’ medication regimens, including
prescribing appropriateness and regimen complexity.
Bakken et al. [
] also reported that the prevalence of PIP in
an IC facility in Norway did not change significantly
between admission and discharge. The authors suggested
that this was due to prescribers’ reluctance to instigate
changes for patients recently discharged from hospital.
Whilst the findings of the present study would suggest that
PIP is not addressed in IC, it was not within the scope of
this study to determine reasons for this. Cullinan et al. [
identified several barriers to behaviour change amongst
prescribers in relation to appropriate prescribing. These
included limited information-technology infrastructure,
insufficient pharmacy input and a lack of geriatric
pharmacotherapy training for prescribers [
Anderson et al. [
] suggested that ‘inertia’ amongst
prescribers plays a key role in the appropriateness of
prescribing. This describes the failure to intervene, because
the unknown consequences that may be associated with the
cessation of a medication are less ‘desirable’ than its
continuation, particularly if the medicine was initiated by
another prescriber [
Unsurprisingly, the number of prescribed medicines in a
patient’s regimen was positively correlated with PIMs. The
association between PIMs and polypharmacy has been
highlighted repeatedly in the literature [
19, 23, 24
Correspondingly, increasing patient comorbidity and
medication regimen complexity were associated with the
identification of PIMs at admission. Medication regimens
can be rationalised in ways that do not compromise the
overall intended therapeutic effect. Elliot et al. [
demonstrated that a pharmacist-led intervention aimed
specifically at rationalising patients’ medication regimens
by reducing their complexity can be successfully
implemented in IC. Finally, it must be noted that whilst efforts to
reduce polypharmacy (and/or medication regimen
complexity) may seem synonymous with improving prescribing
appropriateness, the distinction between appropriate
polypharmacy and inappropriate polypharmacy is not
always clear [
The small sample size obtained from one geographical area
of NI limits the generalisability of the findings.
Furthermore, owing to the small sample size and the associated
risk of a type II error, the significance of the findings
reported should be interpreted with caution. Prescribers
were not given the opportunity to explain their prescribing
decisions for individual patients. Incomplete
documentation of patients’ current diagnoses and biochemical
information in the IC notes may have led to a lower rate of
reporting of PIP in some cases, or a higher rate of reporting
in others (i.e. where a medicine was clinically indicated but
the patient’s notes did not document the indication). Due to
the cross-sectional observational nature of the study it was
not possible to make causal inference with regards to
patient-related factors and the prevalence of PIP in IC.
STOPP/START also have inherent limitations to their use.
There may be a difference between recommendations
derived from evidence and what is in the individual
patient’s best interest [
]. STOPP/START are designed to
be a user-friendly screening tools to aid the identification of
potentially inappropriate prescribing; as such, they are
limited in their ability to account for each patient’s holistic
This study of PIP amongst older adults in IC facilities in NI
has identified PIMs and PPOs in substantial proportions of
patients at both admission to and discharge from the IC
setting. IC patients are typically older adults with marked
levels of comorbidity and complex medication regimens.
IC provides an ideal setting to address PIP and other
medicines management issues with a view to lowering the
risk of avoidable ADEs and associated negative outcomes
in this population.
Acknowledgements We would like to thank all the intermediate care
facility managers and staff for their cooperation.
Funding This work was supported by the Department for
Employment and Learning (DEL) Northern Ireland. The funders had no role
in the design, execution, analysis and interpretation of data, or writing
of the study.
Conflicts of interest The authors declare that they have no conflicts
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1. Melis R , Parker S , Van Eijken M. What is intermediate care? Br Med J. 2004 ; 329 : 360 - 1 .
2. Millar A , Hughes C , Passmore A , Ryan C . Intermediate care: the role of medicines management . Drugs Aging . 2014 ; 31 ( 1 ): 21 - 31 .
3. Millar AN , Hughes CM , Ryan C. ' 'It's very complicated'': a qualitative study of medicines management in intermediate care facilities in Northern Ireland . BMC Health Serv Res . 2015 ; 15 : 216 .
4. Millar AN , Hughes CM , Ryan C. A qualitative study of community pharmacists' awareness of and involvement with intermediate care facilities . Eur J Pers Cent Healthc . 2016 ; 4 ( 1 ): 53 - 60 .
5. Hamilton H , Gallagher P , Ryan C , Byrne S , O'Mahony D. Potentially inappropriate medications defined by STOPP criteria and the risk of adverse drug events in older hospitalized patients . Arch Intern Med . 2011 ; 171 ( 11 ): 1013 - 9 .
6. Ryan C , O'Mahony D , Kennedy J , Weedle P , Byrne S. Potentially inappropriate prescribing in an Irish elderly population in primary care . Br J Clin Pharmacol . 2009 ; 68 ( 6 ): 936 - 47 .
7. Gallagher P , Ryan C , Byrne S , Kennedy J , O'Mahony D. STOPP (screening tool of older person's prescriptions) and START (screening tool to alert doctors to right treatment) . Consensus validation. Int J Clin Pharm Ther . 2008 ; 46 ( 2 ): 72 - 83 .
8. O 'Mahony D , O'Sullivan D , Byrne S , O'Connor MN , Ryan C , Gallagher P. STOPP/START criteria for potentially inappropriate prescribing in older people: version 2 . Age Ageing . 2015 ; 44 ( 2 ): 213 - 8 .
9. Bakken MS , Ranhoff AH , Engeland A , Ruths S. Inappropriate prescribing for older people admitted to an intermediate-care nursing home unit and hospital wards . Scand J Prim Health . 2012 ; 30 ( 3 ): 169 - 75 .
10. Rognstad S , Brekke M , Fetveit A , Spigset O , Wyller TB , Straand J . The Norwegian general practice (NORGEP) criteria for assessing potentially inappropriate prescriptions to elderly patients: a modified Delphi study . Scand J Prim Health . 2009 ; 27 ( 3 ): 153 - 9 .
11. Charlson ME , Pompei P , Ales KL , Mackenzie CR . A new method of classifying prognostic comorbidity in longitudinal studies: development and validation . J Chronic Dis . 1987 ; 40 ( 5 ): 373 - 83 .
12. De Groot V , Beckerman H , Lankhorst GJ , Bouter LM . How to measure comorbidity: a critical review of available methods . J Clin Epidemiol . 2003 ; 56 ( 3 ): 221 - 9 .
13. Joint Formulary Committee. British National Formulary. 68th Ed . London: BMJ Group and Pharmaceutical Press; 2014 . ISBN: 0857111388 .
14. George J , Phun Y , Bailey M , Kong D , Stewart K . Development and validation of the medication regimen complexity index . Ann Pharmacother . 2004 ; 38 ( 9 ): 1369 - 76 .
15. Kongkaew C , Noyce PR , Ashcroft DM . Hospital admissions associated with adverse drug reactions: a systematic review of prospective observational studies . Ann Pharmacother. 2008 ; 42 ( 7-8 ): 1017 - 25 .
16. Glass J , Lanctot K , Herrmann N , Sproule B , Busto U . Sedative hypnotics in older people with insomnia: meta-analysis of risks and benefits . Br Med J. 2005 ; 331 ( 7526 ): 1169 - 73 .
17. Straand J , Rokstad K . General practitioners' prescribing patterns of benzodiazepine hypnotics: Are elderly patients at particular risk for overprescribing? A report from the More and Romsdal prescription study . Scand J Prim Health . 1997 ; 15 ( 1 ): 16 - 21 .
18. Williams ME , Pulliam CC , Hunter R , Johnson TM , Owens JE , Kincaid J , et al. The short-term effect of interdisciplinary medication review on function and cost in ambulatory elderly people . J Am Geriatr Soc . 2004 ; 52 ( 1 ): 93 - 8 .
19. Gallagher P , O'Connor MN , O'Mahony D . Prevention of potentially inappropriate prescribing for elderly patients: a randomized controlled trial using STOPP/START criteria . Clin Pharmacol Ther . 2011 ; 89 ( 6 ): 845 - 54 .
20. Ryan C , O'Mahony D , Kennedy J , Weedle P , Cottrell E , Heffernan M , et al. Potentially inappropriate prescribing in older residents in Irish nursing homes . Age Ageing . 2013 ; 42 ( 1 ): 116 - 20 .
21. Cullinan S , Fleming A , O'Mahony D , Ryan C , O'Sullivan D , Gallagher P , et al. Doctors' perspectives on the barriers to appropriate prescribing in older hospitalized patients: a qualitative study . Br J Clin Pharmacol . 2015 ; 79 ( 5 ): 860 - 9 .
22. Anderson K , Stowasser D , Freeman C , Scott I. Prescriber barriers and enablers to minimising potentially inappropriate medications in adults: a systematic review and thematic synthesis . BMJ Open . 2014 ; 4 ( 12 ):e006544. doi: 10 .1136/bmjopen-2014-006544.
23. Cahir C , Fahey T , Teeling M , Teljeur C , Feely J , Bennett K. Potentially inappropriate prescribing and cost outcomes for older people: a national population study . Br J Clin Pharmacol . 2010 ; 69 ( 5 ): 543 - 52 .
24. Bradley MC , Motterlini N , Padmanabhan S , Cahir C , Williams T , Fahey T , et al. Potentially inappropriate prescribing among older people in the United Kingdom . BMC Geriatr . 2014 ; 14 : 72 .
25. Elliott RA , O'Callaghan C , Paul E , George J . Impact of an intervention to reduce medication regimen complexity for older hospital inpatients . Int J Clin Pharm . 2013 ; 35 ( 2 ): 217 - 24 .
26. Patterson SM , Hughes C , Kerse N , Cardwell CR , Bradley MC . Interventions to improve the appropriate use of polypharmacy for older people . Cochrane Database Syst Rev . 2014 . doi: 10 .1002/ 14651858.CD008165. pub3 .
27. Golomb BA , Chan VT , Evans MA , Koperski S , White HL , Criqui MH . The older the better: Are elderly study participants more non-representative? A cross-sectional analysis of clinical trial and observational study samples . BMJ Open . 2012 ; 2 ( 6 ):e000833. doi: 10 .1136/bmjopen-2012-000833.