Abstract
Background: Co-morbidity is common in older people. A co-morbidity index reduces coexisting illnesses and their severity to a single numerical score, allowing comparison with scores from other patients. Recently, the Medication-Based Disease Burden Index (MDBI) was developed.
Objective: The aim of the study was to assess the MDBI’s validity in hospitalized elderly patients.
Methods: Clinical and demographic data and data on patients’ medications on admission were obtained prospectively. Retrospectively, we applied the MDBI to the patients’ medication regimens, determining their co-morbidity using the Charlson Comorbidity Index and Cumulative Illness Rating Scale for Geriatrics (CIRS-G). The MDBI’s criterion validity was assessed against the Charlson and CIRS-G indices. Convergent and discriminant validities were also assessed. The MDBI’s predictive validity was assessed by its ability to predict 3-month post-discharge readmissions or mortality compared with the Charlson and CIRS-G indices.
Results: MDBI scores were correlated with the Charlson and CIRS-G indices’ scores (r = 0.44 and r = 0.37, respectively [p<0.001]). MDBI, Charlson Co-morbidity Index and CIRS-G scores were correlated with the number of drugs (r = 0.52, r = 0.34 and r = 0.40, respectively [p<0.001]) and were the same in both sexes. No significant differences in MDBI scores were found between cognitively normal and impaired mental status (IMS) patients or between the functionally independent and partially/fully dependent patients. Charlson Comorbidity Index and CIRS-G scores were significantly lower in IMS patients and in dependent patients. The MDBI had no predictive ability for 3-month mortality but had good predictive power for a composite of 3-month mortality or readmissions (odds ratio [OR] 2.99 [95% CI 0.99, 9.03; p = 0.051]). However, CIRS-G and Charlson indices had good predictive ability for mortality (OR 1.50 [95% CI 1.22,1.84; p<0.001] and OR 2.06 [95% CI 1.40, 3.02; p<0.001], respectively) and for a composite of 3-month mortality or readmissions (OR 1.24 [95% CI 1.11, 1.34; p<0.001] and OR 1.39 [95% CI 1.12, 1.72; p = 0.003], respectively).
Conclusions: The MDBI showed satisfactory criterion, convergent and discriminant validities and good predictive validity for mortality or readmission, but failed to differentiate between cognitive and functional patient groups. The MDBI should be investigated in larger studies to determine its validity in settings where medication data rather than diagnostic data are more readily available. In clinical practice with elderly patients, we recommend employing co-morbidity indices that are based on medical records, such as the Charlson Comorbidity Index and CIRS-G.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Yancik R, Ershler W, Satariano W, et al. Report of the National Institute on Aging Task Force on Comorbidity. J Gerontol A Biol Sci Med Sci 2007; 62: 275–80
Gijsen R, Hoeymans N, Schellevis FG, et al. Causes and consequences of comorbidity: a review. J Clin Epidemiol 2001; 54: 661–74
Hall SF. A user’s guide to selecting a comorbidity index for clinical research. J Clin Epidemiol 2006; 59: 849–55
de Groot V, Beckerman H, Lankhorst GJ, et al. How to measure comorbidity: a critical review of available methods. J Clin Epidemiol 2003; 56: 221–9
Lash TL, Mor V, Wieland D, et al. Methodology, design, and analytic techniques to address measurement of comorbid disease. J Gerontol A Biol Sci Med Sci 2007; 62: 281–5
Charlson ME, Pompei P, Ales KL, et al. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987; 40: 373–83
Linn BS, Linn MW, Gurel L. Cumulative illness rating scale. J Am Geriatr Soc 1968; 16: 622–6
Crabtree HL, Gray CS, Hildreth AJ, et al. The Comorbidity Symptom Scale: a combined disease inventory and assessment of symptom severity. J Am Geriatr Soc 2000; 48: 1674–8
Owens WD, Felts JA, Spitznagel Jr EL. ASA physical status classifications: a study of consistency of ratings. Anesthesiology 1978; 49: 239–43
Von Korff M, Wagner EH, Saunders K. A chronic disease score from automated pharmacy data. J Clin Epidemiol 1992; 45: 197–203
Miller MD, Paradis CF, Houck PR, et al. Rating chronic medical illness burden in geropsychiatric practice and research: application of the Cumulative Illness Rating Scale. Psychiatry Res 1992; 41: 237–48
George J, Vuong T, Bailey MJ, et al. Development and validation of the medication-based disease burden index. Ann Pharmacother 2006; 40: 645–50
Mansur N, Weiss A, Hoffman A, et al. Continuity and adherence to long-term drug treatment by geriatric patients after hospital discharge: a prospective cohort study. Drugs Aging 2008; 25: 861–70
Mansur N, Weiss A, Beloosesky Y. Relationship of in-hospital medication modifications of elderly patients to postdischarge medications, adherence, and mortality. Ann Pharmacother 2008; 42: 783–9
Folstein MF, Folstein SE, McHugh PR. “Mini-Mental State”: a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975; 12: 189–98
Beloosesky Y, Grinblat J, Epelboym B, et al. Functional gain of hip fracture patients in different cognitive and functional groups. Clin Rehabil 2002; 16: 321–8
Katz S. Assessing self-maintenance: activities of daily living, mobility and instrumental activities of daily living. J Am Geriatr Soc 1983; 31: 721–7
Ganguli M, Dodge HH, Mulsant BH. Rates and predictors of mortality in an aging, rural, community-based cohort: the role of depression. Arch Gen Psychiatry 2002; 59: 1046–52
Schultz-Larsen K, Rahmanfard N, Kreiner S, et al. Cognitive impairment as assessed by a short form of MMSE was predictive of mortality. J Clin Epidemiol 2008; 61: 1227–33
Chang HH, Tsai SL, Chen CY, et al. Outcomes of hospitalized elderly patients with geriatric syndrome: report of a community hospital reform plan in Taiwan. Arch Gerontol Geriatr 2010; 50Suppl. 1: S30–3
Millán-Calenti JC, Tubío J, Pita-Fernández S, et al. Prevalence of functional disability in activities of daily living (ADL), instrumental activities of daily living (IADL) and associated factors, as predictors of morbidity and mortality. Arch Gerontol Geriatr 2010; 50: 306–10
Vitry A, Wong SA, Roughead EE, et al. Validity of medication-based co-morbidity indices in the Australian elderly population. Aust N Z J Public Health 2009; 33: 126–30
Zekry D, Loures Valle BH, Lardi C, et al. Geriatrics index of comorbidity was the most accurate predictor of death in geriatric hospital among six comorbidity scores. J Clin Epidemiol 2010; 63: 1036–44
Aronow WS. Office management after myocardial infarction. Am J Med 2010; 123: 593–5
Field TS, Benavente OR. Current status of antiplatelet agents to prevent stroke. Curr Neurol Neurosci Rep 2011; 11: 6–14
Hajjar ER, Cafiero AC, Hanlon JT. Polypharmacy in elderly patients. Am J Geriatr Pharmacother 2007; 5: 345–51
Garfinkel D, Mangin D. Feasibility study of a systematic approach for discontinuation of multiple medications in older adults: addressing polypharmacy. Arch Intern Med 2010; 170: 1648–54
Redelmeier DA, Tan SH, Booth GL. The treatment of unrelated disorders in patients with chronic medical diseases. N Engl J Med 1998; 338: 1516–20
Acknowledgements
No sources of funding were used to conduct this study. The authors have no conflicts of interest that are directly relevant to the content of this study.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Beloosesky, Y., Weiss, A. & Mansur, N. Validity of the Medication-Based Disease Burden Index Compared with the Charlson Comorbidity Index and the Cumulative Illness Rating Scale for Geriatrics. Drugs Aging 28, 1007–1014 (2011). https://doi.org/10.2165/11597040-000000000-00000
Published:
Issue Date:
DOI: https://doi.org/10.2165/11597040-000000000-00000