Age-related changes in physical health and increased occurrence of diseases predispose elderly people to adverse health outcomes, including malnutrition. Recent evidence suggests that polypharmacy may promote the occurrence of poor nutritional status, most commonly as a manifestation of adverse drug effects [1,2▪▪–4▪▪]. Concern about the role of drug treatment is relevant, as several studies of elderly populations have shown polypharmacy to be very prevalent . Even so, research on the role of polypharmacy on nutritional status in elderly people is scarce.
Drug treatment may contribute to poor nutritional status, for example, by causing loss of appetite, nausea, diarrhea, weight changes, taste alterations, decrease in saliva secretion, modifications in lipid profile, alterations in electrolyte balance, and changes in glucose metabolism [6,7]. Nutritional status is also of great concern because of its impact on the pharmacology of many drugs . Food can affect on drug absorption and metabolism, which means decreased drug effects or overdose of drugs. Malnutrition may also lead to decreased amount of serum protein, meaning a higher unbound drug fraction. This can lead to increased drug effects, as only unbound drug fractions have pharmacological activity.
Nutritional status is commonly evaluated as a part of comprehensive geriatric assessment by validated tests. It is known that drug treatment may influence both positively and negatively on different health indicators, including nutritional status. When prescribing drugs for elderly people, declined nutritional status means more challenges in balancing between benefits and harms of drug treatment.
Recently, more attention has been given to health-related effects of polypharmacy, but the evidence on associations between polypharmacy and nutritional status is still limited. This review focuses on summarizing the findings published on the relationship between polypharmacy and nutritional status in elderly people. Relevant literature was identified through searches of the PubMed and Scopus.
CHARACTERISTICS OF POLYPHARMACY
There is no generally accepted consensus for the definition of polypharmacy, except that it indicates the use of multiple drugs by a single person . However, most studies have defined polypharmacy quantitatively as a specific number of drugs in use: five or more drugs are used most frequently as a cut-off . A separate definition for excessive polypharmacy, meaning usually the use of nine or 10 or more drugs concomitantly, has also been recently adapted for use [9–12].
Review of published literature has shown a clear worldwide increasing trend in the quantity of drug use over the past decades . A mean number of drugs used by community-dwelling elderly people have varied from 3.5 to 6.9, when taking into account both prescription and over-the-counter drugs [10,13–15]. According to a recent study, cardiovascular drugs (82%), nervous system drugs (62%), drugs for blood and blood forming organs (63%), and drugs for alimentary tract and metabolism (60%) were the most commonly used drug groups in a population-based sample of elderly people aged 75 years and older .
Approximately, every other community-dwelling elderly person have polypharmacy [16–19] and every fifth have excessive polypharmacy [4▪▪,9,13,16]. Studies conducted among institutionalized elderly people have reported about every other patient to have excessive polypharmacy [20–22]. A large European study conducted among elderly people receiving home care services revealed the prevalence of polypharmacy (six or more drugs in use) to be highest in the Czech Republic (86%) and Finland (73%) . The lowest prevalence rates were observed in Norway (34%), the Netherlands (35%), and Italy (36%). The differences in prevalences can be partly explained by country-specific drug policies, prescribing patterns, and refund systems. Differences in socioeconomic status of elderly populations between countries may also influence the reported findings.
ASSESSMENT OF NUTRITIONAL STATUS
The Mini Nutritional Assessment (MNA) test is the most widely used and validated test to assess nutritional status of elderly people [24,25]. The test is composed of 18 measures encompassing anthropometry, dietary assessment, clinical global assessment, and subjective evaluation of health and nutritional status. The total scores of the MNA test range from 0 to 30, with scores 24 or above indicating sufficient nutritional status, 23.5–17 risk of malnutrition, and below 17 malnutrition. Another commonly used nutritional tool is the 10-statement DETERMINE checklist, which is designed to be self-administered but can also be used by healthcare professionals . Statements that cover dietary, general, and social assessments have weighted scores: scores 0–2 reflect good nutritional status, and scores 3–5 moderate and 6–21 high nutritional risk.
Drug use is a domain of the tests used to assess the nutritional state of elderly patients. Both the MNA and DETERMINE include a question on whether the person is taking three or more drugs daily. When this criterion for polypharmacy is used, a high proportion of elderly people fall into this category [27,28]. In addition, the dichotomous question about drug use is relatively crude which limits detailed analysis about the role of drug treatment on nutritional status. A cut-off value for number of drugs, which carries an increased risk for nutritional problems in elderly people, is not known. Apparently, five or more drugs daily would be more appropriate than the currently used three or more drugs. Another solution would be adding more response choices to questions dealing with drug use in the nutritional assessments.
Poor nutritional status is a serious and common problem in elderly people. Recent publications using the MNA test in the assessment indicated that quite a high proportion of community-dwelling (13–34%) [29–32] and a vast majority of institutional living (71–97%) [31,33–36] elderly people are malnourished or at risk of it. A study conducted in low-level care facilities reported that one-third of elderly people are protein malnourished and two-thirds have energy deficits based on information gained from 3-day weighted food records, anthropometric and biochemical indicators .
POLYPHARMACY AND NUTRITIONAL STATUS
The probability of nutritional problems as a consequence of drugs is highest in elderly people suffering from multiple diseases which consequently are treated with multiple drugs. It is apparent that some diseases increase the likelihood of poor nutritional status; thus, the independent role of drugs on nutritional status is challenging to determine. To address this issue, we performed comorbidity-adjusted analyses in the study of community-dwelling elderly people (n = 294, age 75 years or older) which showed excessive polypharmacy to be a significant correlate of declined nutritional status, whereas for polypharmacy (six to nine drugs) no such association was found [4▪▪]. Studies analyzing the number of drugs as a continuous exposure have shown inverse association between the number of drugs and nutritional status [38,39,40▪] but have not determined cut-off values for the risk of malnutrition. On the basis of these findings, it can be assumed that polypharmacy may contribute to poor nutritional status, even beyond current diseases. However, most likely the impact of drugs on nutritional status is significant only when using fairly high numbers of drugs. Further research is also needed to clarify the role of certain specific drug groups on nutritional status.
The majority of studies examining the association between polypharmacy and nutritional status have been conducted with cross-sectional designs. A small study of retirement home residents (n = 81) showed that an increasing number of drugs in use was associated with lower MNA scores . The average number of drugs in those having severe nutritional problems (7.3 drugs, MNA <17) was significantly higher compared to those with better nutritional status (4.5 drugs, MNA 17 or more). However, these results were cross-sectional in nature and lack some potential confounders in adjusting, and therefore results should be interpreted with caution. Studies among elderly hospital patients have also shown that polypharmacy is a predictor of poor nutritional status after adjustments for sociodemographic factors and health status indicators [39,41]. To confirm these findings, larger cohorts of community-dwelling people and hospitalized patients with more complete adjustment with diseases are needed.
A recent study of community-dwelling elderly people (n = 294) reported that in a cross-sectional setting, those having excessive polypharmacy (10 or more drugs in use) had an average of 0.6 points lower MNA-SF scores (maximum 14 points) compared to those without polypharmacy (five or less drugs in use) when adjusted for sociodemographic factors, functional comorbidity index (FCI), and self-reported health status [4▪▪]. However, in prospective analysis, the polypharmacy status did not predict the 3-year change in nutritional status. In further studies, the important viewpoint that should be taken into account is the quality of drug treatment in those having polypharmacy. There are no available studies on the role of inappropriate medication for nutritional status.
The risk of developing malnutrition is particularly high in people with dementing disorders who confront considerable difficulties in their eating as the disease progresses [42,43]. Their poor nutritional status may also reflect the occurrence of nausea and diarrhea, which are the common side-effects of acetylcholinesterase inhibitors used widely in the treatment of Alzheimer's disease . With regard to polypharmacy, a recently published study of demented nursing home patients observed no correlation between the number of drugs and current nutritional status . It is likely that the role of drugs in development of poor nutritional status is not as important as the eating problems related to the disease itself.
POLYPHARMACY AND CHANGES IN WEIGHT
One component of nutritional assessment is weight loss, which can be used as an indicator of insufficient energy intake. A cross-sectional study of community-dwelling elderly persons revealed almost a three-fold risk of experiencing weight loss (≥4.5 kg during a 1-year period) for those using five or more drugs compared to those using less drugs after adjustments for sociodemographic factors, overall health status, diseases, and previous hospitalizations . Another cross-sectional study reported three or more drugs in use to correlate with weight change (BMI less than 20.0 kg/m2 or weight loss of ≥5% or more during the last 6 months) in women, but the association attenuated after adjusting for sociodemographic factors, diseases, and correlates of physical and psychological status [40▪]. Of individual drug groups, the association with weight changes has been reported for some cardiovascular (e.g. cardiac glycosides, and diuretics) drugs and psychotropics (e.g. antipsychotics and antidepressants) [1,46].
In addition to weight loss, also obesity (BMI ≥30 kg/m2 or more) has been found to be associated with polypharmacy [15,47,48▪▪]. In a Swedish study, obese (BMI ≥30.0 kg/m2 or more) elderly people had over two-fold risk of polypharmacy compared to those with lower BMI . However, this finding should be interpreted with caution because of cross-sectional study setting and incomplete adjustments, as only sex, current smoking, self-rated health, diabetes, and hypertension were included in the analysis. Support for this finding was presented in a US study that reported elderly people taking seven or more prescription drugs to have higher BMI than those taking less drugs [48▪▪]. The most likely explanation for these associations is that obese elderly people have greater comorbidity burden, meaning increased need of drug treatments, rather than polypharmacy promoting the weight gain. The cross-sectional findings on associations of polypharmacy and BMI should be interpreted with caution because of incomplete adjustment for diseases [15,48▪▪]. Also, longitudinal studies would provide more reliable evidence about the effects of polypharmacy on body weight.
IMPACT OF DRUGS ON THE INTAKE OF ENERGY AND NUTRIENTS
The main nutritional problem in elderly people is insufficient energy and protein intake, often combined with deficient supply of essential nutrients . It is apparent that aging itself and several diseases often lead to decreased food and concomitant energy and nutrient intake, but side-effects of various drugs (e.g. loss of appetite, gastrointestinal problems, and alterations in body function) may also affect the nutrient intake. This was observed in a study that reported polypharmacy to associate with low energy intake among elderly people . High number of drugs in use means also increased risk of drug–nutrient interactions leading to decreased absorption of essential nutrients [51,52]. In addition, age-related changes in body composition and function alter drug responses but affect also markedly the metabolism and kinetics of nutrients.
The number of studies assessing the effect of polypharmacy on the intake of nutrients is limited and based mainly on cross-sectional studies with incomplete adjustment for confounding factors. In a recent cross-sectional study of community-dwelling elderly (n = 1065) aged over 65 years, the number of drugs in use correlated with worsened quality of diet [3▪▪]. With regard to specific nutrients, the study found a significant decrease in the intake of fiber, several fat-soluble vitamins (A, D, and E), and some water-soluble vitamins (B1, B3, and B7) with increasing number of drugs in use. Contrary, an increased intake of glucose, sodium, and dietary cholesterol with the number of drugs in use was observed. Another study that concentrated more specifically on vitamin status of noninstitutionalized elderly people (n = 102) reported the intake of three or more drugs to associate with decreased concentration of vitamins D, K, and B6[2▪▪]. No association was observed between polypharmacy and concentration of vitamin C. There is also evidence on the association between polypharmacy and low levels of folate [2▪▪,53]. According to a descriptive study among statins users, the levels of vitamin B12, vitamin K, and potassium were lower compared to those not taking statins .
One issue raised in the recent publications was insufficient fiber intake in those having polypharmacy [2▪▪,3▪▪]. A large amount of drugs have anticholinergic effects, which means increased anticholinergic load for those with polypharmacy. Specific attention to fiber and fluid intake should be paid when polypharmacy is present, because constipation is a common adverse effect caused by anticholinergics . It has been reported that about every fifth elderly person uses laxatives [56–59] which calls for increasing use of fibre supplements or adding dietary supply of fiber from whole grains, fruits, and vegetables to the diet of elderly people . Fiber promotes the normal bowel movements and thus acts as a less invasive treatment of constipation than laxatives.
An added concern about glucose balance is that age-related impairments in glucose metabolism result in reduced glycemic control. Drug treatment (e.g. diuretics, beta blockers, and corticosteroids) may also lead to disturbances in glucose homeostasis . In elderly people, sodium levels need to be followed, because the capacity of kidneys in regulating the correct amount of sodium decreases markedly with aging. Some drugs (e.g. diuretics, antidepressants, antipsychotics, and NSAIDs) have modest effect on sodium retention . The clinical significance of these drugs, however, more often is the development of hyponatremia rather than hypernatremia. These drugs may promote hyponatremia especially in elderly people with inappropriate antidiuretic hormone secretion.
Published evidence on polypharmacy relations with quality of diet in elderly people is scarce. The two available studies are cross-sectional and therefore causal relationships between polypharmacy and nutritional status have not been established [2▪▪,3▪▪]. In addition, analyses of these studies were not adjusted for potential confounders, and thus the role of polypharmacy as an independent risk factor cannot be assessed. Reported results in these studies are not fully comparable because of differences in data collection. In the US study, the information was collected by a questionnaire on food consumption, whereas the Austrian study used plasma levels of vitamins as a measure. Properly collected food consumption data offer comprehensive information on diet, whereas hematological and biochemical markers can give information on limited sections of diet only. Combining self-reported data with biochemical markers in longitudinal study designs would be ideal in order to confirm association between polypharmacy and nutritional status.
Previous studies have shown that polypharmacy strongly correlates with unnecessary drug treatment and drug-related problems in elderly people [63–65]. The number of drugs itself is usually a marker of declined health status, and thus it has only a limited role as an independent factor for nutritional status. However, it is possible that problems occurring in drug treatment worsen the overall health of elderly people, and thus promotes also the occurrence of nutritional problems. These call for additional research on the association of polypharmacy with nutritional status, taking into account the rationality of medication and allowing adjustment for disease status.
On the basis of limited current evidence, the independent role of polypharmacy on nutritional status is unclear, calling for more studies on the subject. Results are mainly based on cross-sectional studies, often without proper adjustment for potential confounders. To confirm the association between polypharmacy and nutritional status, more studies of larger populations that allow more complete adjustment for diseases are needed, especially with longitudinal study designs.
Current knowledge on polypharmacy relations with nutritional status emphasizes the idea of adding nutritional evaluations as a routine part of comprehensive geriatric assessment, especially for those elderly people suffering several diseases needing drug treatment. Multiprofessional teams including physician, pharmacist, and dietitian would most probably help to identify earlier those at risk of nutritional problems. Co-operations offer also a comprehensive approach to care and would result in better outcomes in ensuring best possible health for an aging population.
Conflicts of interest
The support for this study was obtained from the Finnish Cultural Foundation (Jyrkkä).
There are no conflicts of interest.
REFERENCES AND RECOMMENDED READING
Papers of particular interest, published within the annual period of review, have been highlighted as:
▪ of special interest
▪▪ of outstanding interest
Additional references related to this topic can also be found in the Current World Literature section in this issue (p. 92).
1. Agostini JV, Han L, Tinetti ME. The relationship between number of medications and weight loss or impaired balance in older adults. J Am Geriatr Soc 2004; 52:1719–1723.
Fabian E, Bogner M, Kickinger A, et al. Intake of medication and vitamin status in the elderly. Ann Nutr Metab 2011; 58:118–125.
This article evaluated the association of polypharmacy (three or more drugs in use) with status of several vitamins among noninstitutionalized elderly people.
Heuberger RA, Caudell K. Polypharmacy and nutritional status in older adults. A cross-sectional study. Drugs Aging 2011; 28:315–323.
In this study, increasing use of drugs was shown to associate with insufficient intake of several macronutrients and micronutrients in community-dwelling elderly people.
Jyrkkä J, Enlund H, Lavikainen P, et al. Association of polypharmacy with nutritional status, functional ability and cognitive capacity over a three-year period in an elderly population. Pharmacoepidemiol Drug Saf 2011; 20:514–522.
A recent study that reports excessive polypharmacy (10 or more drugs), but not polypharmacy (six to nine drugs), to associate independently with declined nutritional status.
6. Fick DM, Cooper JW, Wade WE, et al. Updating the Beers criteria for potentially inappropriate medication use in older adults. Arch Intern Med 2003; 163:2716–2724.
7. Pickering G. Frail elderly, nutritional status and drugs. Arch Gerontol Geriatr 2004; 38:174–180.
8. Fulton MM, Allen ER. Polypharmacy in the elderly: a literature review. J Am Acad Nurse Pract 2007; 17:123–132.
9. Haider SI, Johnell K, Weitoft GR, et al. The influence of educational level on polypharmacy and inappropriate drug use: a register-based study of more than 600 000 older people. J Am Geriatr Soc 2009; 57:62–69.
10. Crentsil V, Ricks MO, Xue QL, Fried LP. A pharmacoepidemiological study of community-dwelling, disabled older women: factors associated with medication use. Am J Geriart Pharmacother 2010; 8:215–224.
12. Kragh A, Elmståhl S, Atroshi I. Older adults’ medication use 6 months before and after hip fracture: a population-based cohort study. J Am Geriatr Soc 2011; 59:863–868.
13. Rajska-Neumann A, Wieczorowska-Tobis K. Polypharmacy and potential inappropriateness of pharmacological treatment among community-dwelling elderly patients. Arch Gerontol Geriatr 2007; 44 (Suppl 1):303–309.
14. Haider SI, Johnell K, Thorslund M, Fastbom J. Analysis of the association between polypharmacy and socioeconomic position among elderly aged ≥77 years in Sweden. Clin Ther 2008; 30:419–427.
15. Moen J, Antonov K, Larsson CA, et al. Factors associated with multiple medication use in different age groups. Ann Pharmacother 2009; 43:1978–1985.
17. Johnell K, Klarin I. The relationship between number of drugs and potential drug–drug interactions in the elderly: a study of over 600 000 elderly patients from the Swedish Prescribed Drug Register. Drug Saf 2007; 30:911–918.
18. Junius-Walker U, Theile G, Hummers-Pradier E. Prevalence and predictors of polypharmacy among older primary care patients in Germany. Fam Pract 2007; 24:14–19.
19. Lam DP, Mak CF, Chan SM, et al. Polypharmacy and inappropriate prescribing in elderly Hong Kong Chinese patients. J Am Geriatr Soc 2010; 58:203–205.
20. Schuler J, Dückelmann C, Beindl W, et al. Polypharmacy and inappropriate prescribing in elderly internal-medicine patients in Austria. Wien Klin Wochenschr 2008; 120:733–741.
21. Dwyer LL, Han B, Woodwell DA, Rechtsteiner EA. Polypharmacy in nursing home residents in the United States: results of the 2004 National Nursing Home Survey. Am J Geriatr Pharmacother 2010; 8:63–72.
22. Harugeri A, Joseph J, Parthasarathi G, et al. Prescribing patterns and predictors of high-level polypharmacy in the elderly population: a prospective surveillance study from two teaching hospital in India. Am J Geriatr Pharmacother 2010; 8:271–280.
23. Fialová D, Topinková E, Gambassi G, et al. Potentially inappropriate medication use among elderly home care patients in Europe. JAMA 2005; 16:1348–1358.
24. Guigoz Y, Vellas B, Garry PJ. Assessing the nutritional status of the elderly: the Mini Nutritional Assessment as part of the geriatric evaluation. Nutr Rev 1996; 54:S59–S65.
25. Bleda MJ, Bolibar I, Parés R, Salvà A. Reliability of the mini nutritional assessment (MNA) in institutionalized elderly people. J Nutr Health Aging 2002; 6:134–137.
26. Posner BM, Jette AM, Smith KW, Miller DR. Nutrition and health risks in the elderly: the nutrition screening initiative. Am J Public Health 1993; 83:972–978.
27. Yap KB, Niti M, Ng TP. Nutrition screening among community-dwelling older adults in Singapore. Singapore Med J 2007; 48:911–916.
28. Cuervo M, García A, Ansorena D, et al. Nutritional assessment interpretation on 22 007 Spanish community-dwelling elders through the Mini Nutritional Assessment test. Public Health Nutr 2008; 12:82–90.
29. Johansson Y, Bachrach-Lindström M, Carstensen J, Ek AC. Malnutrition in a home-living older population: prevalence, incidence and risk factors. A prospective study. J Clin Nutr 2008; 18:1354–1364.
30. Iizaka S, Tadaka E, Sanada H. Comprehensive assessment of nutritional status and associated factors in the healthy, community-dwelling elderly. Geriatr Gerontol Int 2008; 8:24–31.
31. Kaiser MJ, Bauer JM, Rämsch C, et al. Frequency of malnutrition in older adults: a multinational perspective using the Mini Nutritional Assessment. J Am Geriatr Soc 2010; 58:1734–1738.
32. Kaburagi T, Hirasawa R, Yoshino H, et al. Nutritional status is strongly correlated with grip strength and depression in community-living elderly Japanese. Publ Health Nutr 2011. [Epub ahead of print]
34. Smoliner C, Norman K, Wagner KH, et al. Malnutrition and depression in the institutionalised elderly. Br J Nutr 2009; 102:1663–1667.
35. Vanderwee K, Clays E, Bocquaert I, et al. Malnutrition and associated factors in elderly hospital patients: a Belgian cross-sectional, multicentre study. Clin Nutr 2010; 29:469–476.
36. Soini H, Suominen M, Muurinen S, et al. Malnutrition according to the Mini Nutritional Assessment in older adults in different settings. J Am Geriatr Soc 2011; 59:765–766.
37. Woods JL, Walker KZ, Iuliano-Burns S, Strauss BJ. Malnutrition on the menu: nutritional status of institutionalised elderly Australians in low-level care. J Nutr Health Aging 2009; 13:693–698.
38. Griep MI, Mets TF, Collys K, et al. Risk of malnutrition in retirement homes elderly persons measured by the ‘Mini-Nutritional Assessment’. J Gerontol Med Sci 2000; 55A:M57–M63.
39. Chen CCH, Tang ST, Wang C, Huang G-H. Trajectory and determinants of nutritional health in older patients during and six-month posthospitalisation. J Clin Nurs 2009; 18:3299–3307.
Schilp J, Winjhoven HAH, Deeg DJH, Visser M. Early determinants for the development of undernutrition in an older general population: Longitudinal Aging Study Amsterdam. Br J Nutr 2011; 106:708–717.
In this recent study, high medication use was assessed as a potential factor associated with undernutrition in a population-based sample of elderly people.
41. Chen CCH, Bai YY, Huang GH, Tang ST. Revisiting the concept of malnutrition in older people. J Clin Nurs 2007; 16:2015–2026.
42. Isaia G, Mondino S, Germinara C, et al. Malnutrition in an elderly population living at home. Arch Gerontol Geriatr 2011; 53:249–251.
43. Slaughter SE, Eliasziw M, Morgan D, Drummond N. Incidence and predictors of eating disability among nursing home residents with middle-stage dementia. Clin Nutr 2011; 30:172–177.
44. Waldemar G, Dubois B, Emre DM, et al. Recommendations for the diagnosis and management of Alzheimer's disease and other disorders associated with dementia: EFNS guideline. Eur J Neur 2007; 14:e1–e26.
45. Chang CC, Roberts BL. Malnutrition and feeding difficulty in Taiwanese older with dementia. J Clin Nurs 2011; 20:2153–2161.
46. Fox CB, Treadway AK, Blaszczyk AT, Sleeper RB. Megestrol acetate and mirtazapine for the treatment of unplanned weight loss in the elderly. Pharmacotherapy 2009; 29:383–397.
47. Esposti ED, Sturani A, Valpiani G, et al. The relationship between body weight and drug costs: an Italian population-based study. Clin Ther 2006; 28:1472–1481.
Ahn SN, Sharkey JR, Smith ML, et al. Variations in body mass index among older Americans: the roles of social and lifestyle factors. J Aging Health 2011; 23:347–366.
This study shows that polypharmacy (seven or more prescription drugs) associates with high BMI scores, even after extensive adjustments.
49. Raynaud-Simon A, Revel-Delhom C, Hébuterne X. Clinical practice guidelines from the French health high authority: nutritional support strategy in protein-energy malnutrition in the elderly. Clin Nutr 2011; 30:312–319.
50. Shahar D, Shai I, Vardi H, Fraser D. Factors associated with low reported energy intake in the elderly. J Nutr Health Aging 2005; 9:300–304.
51. Thomas JA, Burns RA. Important drug–nutrient interactions in the elderly. Drugs Aging 1998; 13:199–209.
52. Akamine D, Filho MK, Peres CM. Drug–nutrient interactions in elderly people. Curr Opin Clin Nutr Met Care 2007; 10:304–310.
53. Shahar D, Levi M, Kurtz I, et al. Nutritional status in relation to balance and falls in the elderly. Ann Nutr Metab 2009; 54:59–66.
54. Lofgren I, Greene G, Schembre S, et al. Comparison of diet quality, physical activity and biochemical values of older adults either reporting or not reporting use of lipid-lowering medication. J Nutr Health Aging 2010; 14:168–172.
55. Wawruch M, Macugova A, Kostkova L, et al. The use of medications with anticholinergic properties and risk factors for their use in hospitalised elderly patients. Pharmacoepidemiol Drug Saf 2011. [Epub ahead of print]
56. Ruby CM, Fillenbaum GG, Kuchibhatla MN, Hanlon JT. Laxative use in the community-dwelling elderly. Am J Geriatr Pharmacother 2003; 1:11–17.
57. Marfil C, Davies GJ, Dettmar PW. Laxative use and its relationship with straining in a London elderly population: free-living versus institutionalised. J Nutr Health Aging 2005; 9:185–187.
58. Jyrkkä J, Vartiainen L, Hartikainen S, et al. Increasing use of medicines in elderly persons: a five-year follow-up of the Kuopio 75+ Study. Eur J Clin Pharmacol 2006; 62:151–158.
59. Haider SI, Johnell K, Thorslund M, Fastbom J. Trends in polypharmacy and potential drug–drug interactions across educational groups in elderly patients in Sweden from the 1992–2002. Int J Clin Pharmacol Ther 2007; 45:643–653.
60. Donini LM, Savina C, Cannella C. Nutrition in the elderly: role of fiber. Arch Gerontol Geriatr 2009; 49 (Suppl 1):61–69.
61. Chan JC, Cockram CS, Critchley JA. Drug-induced disorders of glucose metabolism. Mechanisms and management. Drug Saf 1996; 15:135–157.
62. Liamis G, Milionis H, Elisaf M. A review of drug-induced hyponatremia. Am J Kidney Dis 2008; 52:144–153.
63. Hajjar ER, Hanlon JT, Sloane RJ, et al. Unnecessary drug use in frail older people at hospital discharge. J Am Geriatr Soc 2005; 53:1518–1523.
64. Nguyen JK, Fouts MM, Kotabe SE, Lo E. Polypharmacy as a risk factor for adverse drug reactions in geriatric nursing home residents. Am J Geriatr Pharmacother 2006; 4:36–41.
65. Gallagher PF, Barry PJ, Ryan C, et al. Inappropriate prescribing in an acute ill population of elderly patients as determined by Beers’ criteria. Age Ageing 2008; 37:96–101.
© 2012 Lippincott Williams & Wilkins, Inc.