Comorbidity and its impact on disability

Contribution of Chronic Conditions to the Disability Burden across Smoking Categories in Middle-Aged Adults, Belgium

INTRODUCTION

Smoking is considered the single most important preventable cause of morbidity and mortality worldwide, contributing to increased incidence and severity of disabling conditions. The aim of this study was to assess the contribution of chronic conditions to the disability burden across smoking categories in middle-aged adults in Belgium.

METHODS

Data from 10,224 individuals aged 40 to 60 years who participated in the 1997, 2001, 2004, or 2008 Health Interview Surveys in Belgium were used. Smoking status was defined as never, former (cessation ≥2 years), former (cessation <2 years), occasional light (<20 cigarettes/day), daily light, and daily heavy (≥20 cigarettes/day). To attribute disability to chronic conditions, binomial additive hazards models were fitted separately for each smoking category adjusted for gender, except for former (cessation <2 years) and occasional light smokers due to the small sample size.

RESULTS

An increasing trend in the disability prevalence was observed across smoking categories in men (never = 4.8%, former (cessation ≥2 years) = 5.8%, daily light = 7.8%, daily heavy = 10.7%) and women (never = 7.6%, former (cessation ≥2 years) = 8.0%, daily light = 10.2%, daily heavy = 12.0%). Musculoskeletal conditions showed a substantial contribution to the disability burden in men and women across all smoking categories. Other important contributors were depression and cardiovascular diseases in never smokers; depression, chronic respiratory diseases, and diabetes in former smokers (cessation ≥2 years); chronic respiratory diseases, cancer, and cardiovascular diseases in daily light smokers; cardiovascular diseases and chronic respiratory diseases in men and depression and diabetes in women daily heavy smokers.

CONCLUSIONS

Beyond the well-known effect of smoking on mortality, our findings showed an increasing trend of the disability prevalence and different contributors to the disability burden across smoking categories. This information can be useful from a public health perspective to define strategies to reduce disability in Belgium.

Acute kidney injury induced by antimicrobial agents in the elderly: awareness and mitigation strategies

The use of antimicrobial agents has increased in recent years as treatments have diversified and resistant bacteria have appeared. With increased use of antimicrobial agents, elderly patients are prone to adverse drug reactions (ADRs) as a result of factors such as drug-drug interactions, polypharmacy, long-term use, and over- or under-dosage. In particular, elderly patients using antimicrobials are at increased risk to develop drug-induced acute kidney injury (AKI), which is the most common severe ADR in such patients. AKI is a serious problem that is associated with mortality amongst hospitalized patients. Antimicrobial-induced AKI can be classified into three different types: acute tubular necrosis (ATN), acute interstitial nephritis (AIN), and renal tubule lumen obstruction. AKI can generally be prevented by proper maintenance of fluid balance. To design dosage regimens that ensure efficient drug excretion via the kidney, it is necessary to accurately estimate renal function; however, the kidney undergoes age-dependent structural and functional alterations over time. Therefore, proper management of antimicrobial agents by an antimicrobial stewardship team may lead to decreased incidence of AKI. This article reviews antimicrobial-induced AKI and discusses potential strategies for increasing awareness of AKI and mitigating its clinical effects.

Impact of Chronic Conditions and Multimorbidity on the Disability Burden in the Older Population in Belgium

BACKGROUND

The increase in longevity along with a high prevalence of chronic conditions contribute to increased disability burden. Despite the high occurrence of multimorbidity observed in advanced ages, most studies are restricted to the investigation of individual diseases. In this study, we assessed the impact of chronic conditions and multimorbidity on the disability burden in the older population in Belgium.

METHODS

Data from 9,482 participants in the 2001, 2004, or 2008 Belgian Health Interview Surveys aged 55 years or older were analyzed. Disability was defined based on the Global Activity Limitation Indicator (GALI). To attribute disability to single chronic conditions and disease pairs, a multiple additive hazard model was fitted.

RESULTS

Musculoskeletal conditions (45.3%), chronic respiratory diseases (11.2%), and cardiovascular diseases (10.2%) diseases were the most frequent conditions. Cardiovascular diseases, the co-occurrence of chronic respiratory diseases and depression, neurological diseases, cancer, and the combination of diabetes and cardiovascular diseases were the top five disabling conditions. The disability prevalence in the older population in Belgium was 35.6% (confidence interval =35.0; 36.2%). The most important contributors to the disability burden were musculoskeletal, cardiovascular, and chronic respiratory diseases.

CONCLUSIONS

The present findings provide a deeper understanding of the role of chronic conditions and multimorbidity on the disability burden in the older population in Belgium. Although the disease pairs showed a low contribution to the disability burden, their occurrence presented a high impact on disability. Prevention strategies to tackle disability should target the main contributors to the disability burden and the most disabling conditions/disease pairs, especially in the clinical practice.

Excess weight and disability among the elderly in Argentina

The aim of this paper is to analyze the relationship between excess weight and the condition of disability among elderly people in Argentina and to assess the extent to which a protective factor could be operating that reduces or mitigates the effect of overweight on the loss of functional skills in people over 64 years of age. In order to do so, microdata from Argentina's 2009 National Survey of Risk Factors [Encuesta Nacional de Factores de Riesgo] was utilized. To measure the association among overweight, obesity and disability status, as well as the interaction of weight status and age, logistic regression models were estimated. The results indicate that although overweight and obesity have a positive net effect on the occurrence of disabilities, this effect is lower among people 64 years of age and older. This result could be suggesting that among older people a protective factor is at work that, while not reversing the direct relationship between excess weight and disability, seems to attenuate it.

A comorbidity prognostic effect on post-hospitalization outcome in a geriatric rehabilitation setting: the pivotal role of functionality, assessed by mediation model, and association with the Brass index

BACKGROUND

Discharge planning is a critical feature of hospital's care in geriatric rehabilitation centers. The aim of this study was to evaluate the effects of comorbidity and functionality in identifying patients who are at risk of discharge problems. We also evaluate the association between Blaylock Risk Assessment Screening Score, BRASS index (BI), and post-hospitalization outcome (PHO).

METHODS

Eighty patients (58 women and 22 men, with mean age equal to 83.28 ± 6.77 years) at geriatric rehabilitation division admission were screened with Geriatric Multidimensional Assessment (GMA). Then, BI and PHO were evaluated (mean follow-up time was 205.1 ± 95.8 days). By Structural Equation Model, we evaluated the existing causal relationships between comorbidity, functionality and PHO, elements of GMA, and the association between PHO and BI.

RESULTS

Comorbidity acted on PHO through functionality with indirect effect only (+0.703, P = 0.019). So, the functionality assumes a pivotal role of the causal relationship comorbidity to PHO. BI is positively associated with PHO: correlation returned was equal to +0.313 (P = 0.019).

CONCLUSIONS

The comorbidity has a role in getting worse PHO, but its effect is possible only through the mediation of functional status. The study also demonstrated the positive association between BI and PHO.

Contribution of chronic diseases to the mild and severe disability burden in Belgium

BACKGROUND

Population aging accompanied by an increased longevity with disability has raised international concern, especially due to its costs to the health care systems. Chronic diseases are the main causes of physical disability and their simultaneous occurrence in the population can impact the disablement process, resulting in different severity levels. In this study, the contribution of chronic diseases to both mild and severe disability burden in Belgium was investigated.

METHODS

Data on 21 chronic diseases and disability from 35,799 individuals aged 15 years or older who participated in the 1997, 2001, 2004, or 2008 Belgian Health Interview Surveys were analysed. Mild and severe disability were defined based on questions related to six activities of daily living and/or mobility limitations. To attribute disability by severity level to selected chronic diseases, multiple additive hazard models were fitted to each disability outcome, separately for men and women.

RESULTS

A stable prevalence of mild (5 %) and severe (2-3 %) disability was observed for the Belgian population aged 15 years or older between 1997 and 2008. Arthritis was the most important contributor in women with mild and severe disability. In men, low back pain and chronic respiratory diseases contributed most to the mild and severe disability burden, respectively. The contribution also differed by age: for mild disability, depression and chronic respiratory diseases were important contributors among young individuals, while heart attack had a large contribution for older individuals. For severe disability, neurological diseases and stroke presented a large contribution in young and elderly individuals, respectively.

CONCLUSIONS

Our results indicate that the assessment of the contribution of chronic diseases on disability is more informative if different levels of disability are taken into consideration. The identification of diseases which are related to different levels of disability - mild and severe - can assist policymakers in the definition and prioritisation of strategies to tackle disability, involving prevention, rehabilitation programs, support services, and training for disabled individuals.

The impact of multimorbidity on adult physical and mental health in low- and middle-income countries: what does the study on global ageing and adult health (SAGE) reveal?

BACKGROUND

Chronic diseases contribute a large share of disease burden in low- and middle-income countries (LMICs). Chronic diseases have a tendency to occur simultaneously and where there are two or more such conditions, this is termed as 'multimorbidity'. Multimorbidity is associated with adverse health outcomes, but limited research has been undertaken in LMICs. Therefore, this study examines the prevalence and correlates of multimorbidity as well as the associations between multimorbidity and self-rated health, activities of daily living (ADLs), quality of life, and depression across six LMICs.

METHODS

Data was obtained from the WHO's Study on global AGEing and adult health (SAGE) Wave-1 (2007/10). This was a cross-sectional population based survey performed in LMICs, namely China, Ghana, India, Mexico, Russia, and South Africa, including 42,236 adults aged 18 years and older. Multimorbidity was measured as the simultaneous presence of two or more of eight chronic conditions including angina pectoris, arthritis, asthma, chronic lung disease, diabetes mellitus, hypertension, stroke, and vision impairment. Associations with four health outcomes were examined, namely ADL limitation, self-rated health, depression, and a quality of life index. Random-intercept multilevel regression models were used on pooled data from the six countries.

RESULTS

The prevalence of morbidity and multimorbidity was 54.2 % and 21.9 %, respectively, in the pooled sample of six countries. Russia had the highest prevalence of multimorbidity (34.7 %) whereas China had the lowest (20.3 %). The likelihood of multimorbidity was higher in older age groups and was lower in those with higher socioeconomic status. In the pooled sample, the prevalence of 1+ ADL limitation was 14 %, depression 5.7 %, self-rated poor health 11.6 %, and mean quality of life score was 54.4. Substantial cross-country variations were seen in the four health outcome measures. The prevalence of 1+ ADL limitation, poor self-rated health, and depression increased whereas quality of life declined markedly with an increase in number of diseases.

CONCLUSIONS

Findings highlight the challenge of multimorbidity in LMICs, particularly among the lower socioeconomic groups, and the pressing need for reorientation of health care resources considering the distribution of multimorbidity and its adverse effect on health outcomes.

The added effect of comorbidity on health-related quality of life in patients with asthma

PURPOSE

To examine the effect of comorbidities on health-related quality of life (HRQoL) and their interaction with asthma control.

METHODS

In a random sample of adults with asthma, we measured generic (EQ5D) and disease-specific (AQ5D) utility scores. Asthma symptom control was determined using the 2014 Global Initiative for Asthma Management Strategy. Comorbidity scores were calculated using a validated questionnaire. We used two-part regression models to measure the adjusted difference in utility across levels of symptom control and comorbidity scores and to examine the relative role of symptom control and comorbidity in explaining the variation in HRQoL.

RESULTS

A total of 2,299 observations from 460 adult patients (mean age 52 years, 67 % women) were included. Compared to controlled asthma, uncontrolled asthma was associated with -0.018 reduction (95 % CI -0.028, -0.009) in EQ5D and -0.076 reduction (95 % CI -0.115, -0.052) in AQ5D utilities. An increase by one standard deviation in comorbidity score relative to the mean was associated with a change of -0.029 (95 % CI -0.043, -0.016) in EQ5D and -0.010 (95 % CI -0.020, -0.004) in AQLQ utilities. The impact of comorbidity was greater than asthma symptom control in explaining EQ5D variance (12 vs. 1 %) but smaller in explaining AQ5D variance (3 vs. 12 %).

CONCLUSIONS

Generic and disease-specific HRQoL instruments differentially capture the impact of symptom control and comorbidity in asthma. The selection of HRQoL instruments for asthma studies should depend on the prevalence of comorbidity in the target population and the impact of interventions on asthma control and comorbidity.

Childhood Conditions and Multimorbidity Among Older Adults

OBJECTIVES

This research tests whether childhood conditions are associated with trajectories of chronic conditions among older adults.

METHODS

Using data from the Health and Retirement Study (1992-2008), a series of hierarchical linear models are used to estimate number of chronic conditions at survey midpoint and the rate of increase in chronic conditions across 18 years of data.

RESULTS

Results suggest that lower childhood socioeconomic status (SES) and poor childhood health are associated with increased number of chronic conditions; however, childhood SES is no longer associated with chronic conditions after adjustment for adult SES and adult health. Poor childhood health continues to be associated with total number of chronic conditions after adjustment for adult SES and health. Rate of change in chronic conditions was not associated with childhood conditions. Results from a multinomial logistic regression model further indicated that the association between childhood conditions and adult multimorbidity increased at higher levels of multimorbidity.

DISCUSSION

This research adds to the evidence that early life conditions have a lasting influence on adult health, and that their influence may be independent of adult health and SES.

Multiple conditions: exploring literature from the consumer perspective in Australia

BACKGROUND

Following a workshop with people with multiple conditions, the Chronic Illness Alliance undertook a literature review to explore current literature about multiple conditions.

METHODS

The literature search was performed using Medline, CINAHL, Google Scholar and Cochrane Library employing an extensive list of search terms and limited to English language journals between 1999 and 2009. Inclusion criteria for articles were those articles focussing on issues identified by consumers with more than one chronic illness and the health services working with them.

RESULTS

The results reported in this article are definitions of multiple conditions, safety and quality of services, risks and benefits of treatments for multiple and rare conditions and coordination of services.

DISCUSSION

The impact of multiple conditions or multimorbidities on health services has been researched internationally and identifies the barriers to good health care when multiple conditions are not recognized. While the issues for consumers with more than one condition are not well recognized, the barriers identified by the literature are of great importance to consumers.

CONCLUSIONS

This review demonstrates that services and policies in Australia require specific reforms to better meet the needs of people with multiple conditions.

Contribution of chronic diseases to the disability burden in a population 15 years and older, Belgium, 1997-2008

Background

Age-associated disability reduces quality of life in older populations and leads to wide-range implications for social and health policy. The identification of diseases that contribute to the disability burden is crucial to the development of prevention and intervention strategies to reduce disability. In this study, we assessed the contribution of chronic diseases to the prevalence of disability in Belgium.

Methods

Data from 35,837 individuals aged 15 years or older who participated in the 1997, 2001, 2004, or 2008 Belgian Health Interview Surveys were used. Disability was defined as difficulties in doing at least one of six activities of daily living (transfer in and out of bed, transfer in and out of chair, dressing, washing hands and face, feeding, and going to the toilet) and/or mobility limitations (ability to walk without stopping less than 200 m). Multiple additive regression models were fitted separately for men and women to estimate the age-specific background disability rate (experienced by everyone, independent of the presence of specific diseases) and disease-specific disability rates (disability rate in subjects who reported selected chronic diseases).

Results

Musculoskeletal, cardiovascular, and respiratory diseases were the main contributors to the disability burden in Belgium. Musculoskeletal diseases were the most prevalent diseases in men and women in all age groups. Neurological diseases and stroke were the most disabling diseases, i.e. caused the highest level of disability among the diseased individuals, in all age groups for men and women, respectively. Back pain was the main cause of disability in men aged 15 to 64 years, while heart attack was the major contributor to the disability prevalence in men aged 65 or older. Likewise, arthritis was the main cause of disability among women across all age groups. Depression was also an important contributor in young subjects (15–54 years). Cancer was not an important contributor to the disability prevalence in Belgium.

Conclusions

To reduce the burden of disability in Belgium, interventions should target musculoskeletal, cardiovascular and respiratory diseases especially among elderly. Furthermore, attention should also be given to depression in young individuals.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1574-z) contains supplementary material, which is available to authorized users.

Disability and care needs among older Americans

CONTEXT

The cost of late-life dependency is projected to grow rapidly as the number of older adults in the United States increases in the coming decades. To provide a context for framing relevant policy discussions, we investigated activity limitations and assistance, care resources, and unmet need for a national sample of older adults.

METHODS

We analyzed the 2011 National Health and Aging Trends Study, a new national panel study of more than 8,000 Medicare enrollees.

FINDINGS

Nearly one-half of older adults, or 18 million people, had difficulty or received help in the last month with daily activities. Altogether, 1 in 4 older adults receiving help lived in either a supportive care (15%) or a nursing home (10%) setting. Nearly 3 million received assistance with 3 or more self-care or mobility activities in settings other than nursing homes, and a disproportionate share of persons at this level had low incomes. Nearly all older adults in settings other than nursing homes had at least 1 potential informal care network member (family or household member or close friend), and the average number of network members was 4. Levels of informal assistance, primarily from family caregivers, were substantial for older adults receiving help in the community (164 hours/month) and living in supportive care settings (50 hours/month). Nearly all of those getting help received informal care, and about 3 in 10 received paid care. Of those who had difficulty or received help in settings other than nursing homes, 32% had an adverse consequence in the last month related to an unmet need; for community residents with a paid caregiver, the figure was nearly 60%.

CONCLUSIONS

The older population-especially those with few economic resources-has substantial late-life care needs. Policies to improve long-term services and supports and reduce unmet need could benefit both older adults and those who care for them.

Do Higher Levels of Resilience Buffer the Deleterious Impact of Chronic Illness on Disability in Later Life?

PURPOSE OF THE STUDY

In examining the ability of resilience, or the ability to navigate adversity in a manner that protects well-being, to buffer the impact of chronic disease onset on disability in later life, the authors tested 2 hypotheses: (a) People with greater levels of resilience will have lower levels of disability and (b) resilience will moderate the association between the onset of a new chronic condition and subsequent disability.

DESIGN AND METHODS

This study used a sample of 10,753 Americans between the ages of 51 and 98, derived from 3 waves of the Health and Retirement Study (2006-2010). Ordinary least squares regression was used to estimate the impact of resilience on changes in disability (measured as difficulty with activities of daily living [ADLs] and instrumental activities of daily living [IADLs]) over a 2-year period using a simplified resilience score.

RESULTS

Resilience protects against increases in ADL and IADL limitations that are often associated with aging. Resilience mitigates a considerable amount of the deleterious consequences related to the onset of chronic illness and subsequent disability.

IMPLICATIONS

Our results support our hypotheses and are consistent with claims that high levels of resilience can protect against the negative impact of disability in later life.

Does walking speed mediate the association between visual impairment and self-report of mobility disability? The Salisbury Eye Evaluation Study

OBJECTIVES

To determine whether performance speeds mediate the association between visual impairment and self-reported mobility disability over an 8-year period.

DESIGN

Longitudinal analysis.

SETTING

Salisbury, Maryland.

PARTICIPANTS

Salisbury Eye Evaluation Study participants aged 65 and older (N=2,520).

MEASUREMENTS

Visual impairment was defined as best-corrected visual acuity worse than 20/40 in the better-seeing eye or visual field less than 20°. Self-reported mobility disability on three tasks was assessed: walking up stairs, walking down stairs, and walking 150 feet. Performance speed on three similar tasks was measured: walking up steps (steps/s), walking down steps (steps/s), and walking 4 m (m/s).

RESULTS

For each year of observation, the odds of reporting mobility disability was significantly greater for participants who were visually impaired (VI) than for those who were not (NVI) (odds ratio (OR) difficulty walking up steps=1.58, 95% confidence interval (CI)=1.32-1.89; OR difficulty walking down steps=1.90, 95% CI=1.59-2.28; OR difficulty walking 150 feet=2.11, 95% CI=1.77-2.51). Once performance speed on a similar mobility task was included in the models, VI participants were no longer more likely to report mobility disability than those who were NVI (OR difficulty walking up steps=0.84, 95% CI=0.65-1.11; OR difficulty walking down steps=0.96, 95% CI=0.74-1.24; OR difficulty walking 150 feet=1.22, 95% CI=0.98-1.50).

CONCLUSION

Slower performance speed in VI individuals largely accounted for the difference in the odds of reporting mobility disability, suggesting that VI older adults walk slower and are therefore more likely to report mobility disability than those who are NVI. Improving mobility performance in older adults with visual impairment may minimize the perception of mobility disability.

An examination of adverse asthma outcomes in U.S. Adults with multiple morbidities

RATIONALE

More Americans are managing multiple chronic conditions. Little is known regarding combinations of multiple chronic conditions with asthma.

OBJECTIVES

To examine the prevalence and demographic distribution of five common chronic conditions (arthritis, heart disease, cancer, diabetes, and hypertension) in adults with and without asthma and the adverse asthma outcomes associated with multiple chronic conditions.

METHODS

Cross-sectional interview data from the National Health and Nutrition Examination Survey were analyzed (n = 22,172) between 2003 and 2010. Bivariate analysis methods and multivariate generalized linear regression were used to examine associations.

MEASUREMENTS AND MAIN RESULTS

Of the 10% of subjects with asthma, 54% had one or more coexisting health condition(s). The prevalence of two or three or more other chronic conditions was greater among those with asthma compared with those without (P < 0.001). Common comorbidities with asthma were hypertension (34%) and arthritis (31%). For every additional comorbid chronic condition, there was an increase in the prevalence of reported asthma symptom episodes (prevalence ratio [PR], 1.06; 95% confidence interval [CI], 1.00-1.13), frequent activity limitation (PR, 1.14; 95% CI, 1.04-1.25), sleep disturbances (PR, 1.22; 95% CI, 1.04-1.43), and emergency department visit for asthma (PR, 1.45; 95% CI, 1.19-1.76) when adjusted for socioeconomic and demographic factors and body mass index. The population-attributable risk for emergency department visits for asthma among individuals with asthma who have other chronic comorbidities was 19.5%.

CONCLUSIONS

Half of the adult population with asthma in the United States suffers from comorbid conditions, which are associated with adverse asthma-related outcomes and account for up to 20% of emergency room visits for asthma.

Associations between cardiovascular disease severity, osteoarthritis co-morbidity and physical health: a population-based study

OBJECTIVE

The aim of this study was to investigate the interaction between cardiovascular disease severity and OA co-morbidity on physical health.

METHODS

A baseline questionnaire was mailed to 9676 patients aged ≥40 years from UK family practices. A priori exclusive morbidity groups were constructed as follows, based on records 3 years before baseline: (i) reference group--neither cardiovascular disease nor OA; (ii) cardiovascular disease severity index groups--with hypertension, ischaemic heart disease or heart failure without OA; (iii) OA index group without cardiovascular disease and (iv) co-morbid severity groups with hypertension, ischaemic heart disease or heart failure with OA. Adjusted associations between morbidity groups and physical health [mean physical component summary (PCS) score based on the 12-item Short Form Health Survey (SF-12)] compared with the reference group were assessed using linear regression methods.

RESULTS

A total of 5426 patients responded to the baseline questionnaire (56% response). The adjusted mean difference in PCS score between the reference group and the cardiovascular disease index were -2.4 (95% CI -3.4, -1.4) for hypertension, -5.3 (-6.3, -4.3) for ischaemic heart disease and -11.8 (-13.6, -9.9) for heart failure. The difference in the score for the index OA group was -5.6 (-6.5, -4.6). Estimates for co-morbid OA groups were -6.8 (-7.9, -5.7) for hypertension, -9.1 (-10.6, -7.6) for ischaemic heart disease and -12.8 (-16.0, -9.7) for heart failure.

CONCLUSION

In cardiovascular populations with differing severity, the co-morbid addition of OA was associated with incrementally poorer physical health, but such interactions were less than additive.

Urinary incontinence and disability in community-dwelling women: a cross-sectional study

AIMS

Disability, an individual's reduced capacity to perform physical tasks encountered in daily routine, is associated with urinary incontinence in the elderly. Our objective was to determine if urinary incontinence is associated with disability in community-dwelling women 40 years and older.

METHODS

Cross-sectional study among US women ≥40 years (n = 4,458) from National Health and Nutrition Examination Surveys 2005-2010. We estimated the age-stratified weighted prevalence and factors independently associated with disability (Activities of Daily Living (ADLs), Instrumental Activities of Daily Living (IADLs), mobility, and functional limitations) in women with and without urinary incontinence while controlling for confounders of the association between disability and urinary incontinence.

RESULTS

The weighted prevalence of all disabilities was higher in women with urinary incontinence than women without urinary incontinence across most decades of life with the greatest difference in the prevalence of mobility disabilities: 40-49 years (12.1% vs. 7.0%), 50-59 years (17.0% vs. 9.2%), 60-69 years (28.3% vs. 19.8%), and 70+ years (43.8% vs. 33.0%, all P < 0.05). On multivariable analysis, after controlling for the confounding effect of age, co-morbidities, and income-poverty ratio, urinary incontinence was weakly associated with disabilities. The adjusted odds ratio (95% confidence interval) of disabilities for urinary incontinence was ADL 1.96 (1.07, 3.58), IADL 1.18 (0.78, 1.78), mobility 1.26 (1.01, 1.56), and functional limitations 1.36 (1.07, 1.73).

CONCLUSIONS

Urinary incontinence is weakly associated with disabilities and cannot be implicated as a cause of disability in community dwelling women.

Multimorbidity and evidence generation

Most people with a chronic disease actually have more than one, a condition known as multimorbidity. Despite this, the evidence base to prevent adverse disease outcomes has taken a disease-specific approach. Drawing on a conference, Improving Guidelines for Multimorbid Patients, the goal of this paper is to identify challenges to the generation of evidence to support the care of people with multimorbidity and to make recommendations for improvement. We identified three broad categories of challenges: 1) challenges to defining and measuring multimorbidity; 2) challenges related to the effects of multimorbidity on study design, implementation and analysis; and 3) challenges inherent in studying heterogeneity of treatment effects in patients with differing comorbid conditions. We propose a set of recommendations for consideration by investigators and others (reviewers, editors, funding agencies, policymaking organizations) involved in the creation of evidence for this common type of person that address each of these challenges. The recommendations reflect a general approach that emphasizes broader inclusion (recruitment and retention) of patients with multimorbidity, coupled with more rigorous efforts to measure comorbidity and comorbidity burden and the influence of multimorbidity on outcomes and the effects of therapy. More rigorous examination of heterogeneity of treatment effects requires careful attention to prioritizing the most important comorbid-related questions, and also requires studies that provide greater statistical power than conventional trials have provided. Relatively modest changes in the orientation of current research along these lines can be helpful in pointing to and partially addressing selected knowledge gaps. However, producing a robust evidence base to support patient-centered decision making in complex individuals with multimorbidity, exposed to many different combinations of potentially interacting factors that can modify the risks and benefits of therapies, is likely to require a clinical research enterprise fundamentally restructured to be more fully integrated with routine clinical practice.

Multimorbidity patterns: a systematic review

OBJECTIVES

The aim of this review was to identify studies on patterns of associative multimorbidity, defined as the nonrandom association between diseases, focusing on the main methodological features of the studies and the similarities among the detected patterns.

STUDY DESIGN AND SETTING

Studies were identified through MEDLINE and EMBASE electronic database searches from their inception to June 2012 and bibliographies.

RESULTS

The final 14 articles exhibited methodological heterogeneity in terms of the sample size, age and recruitment of study participants, the data source, the number of baseline diseases considered, and the statistical procedure used. A total of 97 patterns composed of two or more diseases were identified. Among these, 63 patterns were composed of three or more diseases. Despite the methodological variability among studies, this review demonstrated relevant similarities for three groups of patterns. The first one comprised a combination of cardiovascular and metabolic diseases, the second one was related with mental health problems, and the third one with musculoskeletal disorders.

CONCLUSION

The existence of associations beyond chance among the different diseases that comprise these patterns should be considered with the aim of directing future lines of research that measure their intensity, clarify their nature, and highlight the possible causal underlying mechanisms.

Quality of care for patients with multiple chronic conditions: the role of comorbidity interrelatedness

Multimorbidity--the presence of multiple chronic conditions in a patient--has a profound impact on health, health care utilization, and associated costs. Definitions of multimorbidity in clinical care and research have evolved over time, initially focusing on a patient's number of comorbidities and the associated magnitude of required care processes, and later recognizing the potential influence of comorbidity characteristics on patient care and outcomes. In this article, we review the relationship between multimorbidity and quality of care, and discuss how this relationship may be mediated by the degree to which conditions interact with one another to generate clinical complexity (comorbidity interrelatedness). Drawing on established theoretical frameworks from cognitive engineering and biomedical informatics, we describe how interactions among conditions result in clinical complexity and may affect quality of care. We discuss how this comorbidity interrelatedness influences the value of existing quality guidelines and performance metrics, and describe opportunities to quantify this construct using data widely available through electronic health records. Incorporating comorbidity interrelatedness into conceptualizations of multimorbidity has the potential to enhance clinical and research efforts that aim to improve care for patients with multiple chronic conditions.

A longitudinal study of the association between visual impairment and mobility performance in older adults: the salisbury eye evaluation study

Few longitudinal studies have examined how visual impairment affects mobility as people age. Data from the Salisbury Eye Evaluation Study, a population-based sample of 2,520 adults aged 65 years and older, were used to investigate the longitudinal association between visual impairment and mobility. Baseline, 2-year, 6-year, and 8-year visits occurred between 1993 and 2001. Mobility was assessed by measuring speeds on the following 3 tasks: walking up 7 steps, walking down 7 steps, and walking 4 m. Random-effects linear regression was used to model factors affecting speed. For each year of observation, speeds declined, and the visually impaired had significantly slower speeds than the non--visually impaired on all 3 tests after accounting for other covariates (βwalking up steps = -0.08 steps/second, 95% confidence interval (CI): -0.10, -0.06; βwalking down steps = -0.11 steps/second, 95% CI: -0.14, -0.08; and βwalking 4 m = -0.08 m/second, 95% CI: -0.10, -0.06). However, the interaction between years since baseline and visual impairment status was not significant, indicating that mobility speeds declined at a similar rate in the visually impaired and the non--visually impaired. These results suggest that the impact of visual impairment on speed is significant but does not change as people age.

Diabetes predicts long-term disability in an elderly urban cohort: the Northern Manhattan Study

PURPOSE

There are limited data on vascular predictors of long-term disability in Hispanics. We hypothesized that (1) functional status declines over time and (2) vascular risk factors predict functional decline.

METHODS

The Northern Manhattan Study contains a population-based study of 3298 stroke-free individuals aged 40 years or older, followed for median 11 years. The Barthel Index (BI) was assessed annually. Generalized estimating equations and Cox models were adjusted for demographic, medical, and social risk factors. Stroke and myocardial infarction occurring during follow-up were censored in sensitivity analysis. Secondarily, motor and nonmotor domains of the BI were analyzed.

RESULTS

Mean age (standard deviation) of the cohort (n = 3298) was 69.2 (10) years, 37% were male, 52% Hispanic, 22% diabetic, and 74% hypertensive. There was a mean annual decline of 1.02 BI points (P < .0001). Predictors of decline in BI included age, female sex, diabetes, depression, and normocholesterolemia. Results did not change with censoring. We found similar predictors of BI for motor and nonmotor domains.

CONCLUSION

In this large, population-based, multiethnic study with long-term follow-up, we found a 1% mean decline in function per year that did not change when vascular events were censored. Diabetes predicted functional decline in the absence of clinical vascular events.

Increased risk for chronic comorbid disorders in patients with inflammatory arthritis: a population based study

Background

Studies determining the development of a wide variety of different comorbid disorders in inflammatory arthritis (IA) patients are scarce, however, this knowledge could be helpful in optimising preventive care in IA patients. The aim of this study is to establish the risk that new chronic comorbid disorders in newly diagnosed patients with IA in a primary care setting are developed.

Methods

This is a nested-case–control study from 2001–2010 using data from electronic medical patient records in general practice. In total, 3,354 patients with newly diagnosed IA were selected. Each patient was matched with two control patients of the same age and sex in the same general practice. The development of 121 chronic comorbid disorders of index and control patients was compared using Cox regression.

Results

After a median follow-up period of 2.8 years, 56% of the IA-patients had developed at least one chronic comorbid disorder after the onset of IA, compared to 46% of the control patients (p < 0.05). The most frequent developed comorbid disorders after the onset of IA were of cardiovascular (23%), and musculoskeletal (17%) origin. The highest hazard ratios (HRs) were found for anaemia (HR 2.0 [95% CI: 1.4-2.7]) osteoporosis (HR 1.9 [1.4-2.4]), and COPD (HR 1.8 [1.4-2.3]).

Conclusion

Patients with IA developed more chronic comorbid disorders after the onset of IA than one might expect based on age and sex. Since comorbidity has a large impact on the disease course, quality of life, and possibly on treatment itself, prevention of comorbidity should be one of the main targets in the treatment of IA patients.

Prevalence of chronic diseases at the onset of inflammatory arthritis: a population-based study

OBJECTIVE

Little is known about the presence of chronic morbidity in inflammatory arthritis (IA) patients at disease onset. Previous studies have been mainly performed in established IA patients or they focus on isolated co-morbid diseases. Our aim was to determine the prevalence of chronic diseases at the onset of IA and to determine whether this is different from the number that one might expect based on age and sex. Patients and methods. A nested case-control study from 2001 to 2010 using data from patient electronic medical records in general practice. Totally, 3354 patients with newly diagnosed IA were included. Each patient was matched on age, sex and general practice with two control patients. In total, 121 different chronic diseases were studied.

RESULTS

In total, 70% of the IA patients had at least one chronic disease at the onset of IA, compared with 59% of the control patients (P < 0.001). The highest prevalence in IA patients was found for cardiovascular diseases (35%), musculoskeletal diseases (27%) and neurological diseases (22%). Compared with the control patients, patients with IA had the highest increased risk for musculoskeletal diseases [odds ratio, OR = 1.7 (95% confidence interval: 1.6-19)] and for neurological diseases [OR = 1.6 (1.4-1.7)] at the onset of IA.

CONCLUSION

At the onset of IA, nearly three-quarters of patients with IA had at least one other chronic disease. Since multi-morbidity affects treatment and outcome of the IA patient, these diseases should be taken into account when treating IA patients.

The coexistence of terms to describe the presence of multiple concurrent diseases

Background

Consensus on terminology for multiple diseases is lacking. Because of the clinical relevance and social impact of multiple concurrent diseases, it is important that concepts are clear.

Objective

To highlight the diversity of terms in the literature referring to the presence of multiple concurrent diseases/conditions and make recommendations.

Design

A bibliometric analysis of English-language publications indexed in the MEDLINE database from 1970 to 2012 for the terms comorbidity, multimorbidity, polymorbidity, polypathology, pluripathology, multipathology, and multicondition, and a review of definitions of multimorbidity found in English-language publications indexed from 1970 to 2012 in the MEDLINE and SCOPUS databases.

Results

Comorbidity was used in 67,557 publications, multimorbidity in 434, and the other terms in three to 31 publications. At least 144 publications used the term comorbidity without referring to an index disease. Thirteen general definitions of multimorbidity were identified, but only two were frequently used (91% of publications). The most frequently used definition (48% of publications) was “more than one or multiple chronic or long-term diseases/conditions”. Multimorbidity was not defined in 51% of the publications using the term.

Conclusions

Comorbidity was overwhelmingly used to describe any clinical entity coexisting with an index disease under study. Multimorbidity was the term most frequently used when no index disease was designated. Several definitions of multimorbidity were found. However, most authors using the term did not define it. The use of clearly defined terms in the literature is recommended until a general consensus on the terminology of multiple coexistent diseases is reached.

Journal of Comorbidity 2013;3:4–9

[Chronic disease, mortality and disability in an elderly Spanish population: the FRADEA study]

INTRODUCTION

The objective of this study was to analyse the relationships between the major chronic diseases and multiple morbidity, with mortality, incident disability in basic activities of daily living, and loss of mobility in the elderly.

MATERIAL AND METHODS

A total of 943 participants were selected from the FRADEA Study, using available baseline data of chronic diseases, and at the follow-up visit of mortality, incident disability, and loss of mobility. The analysis was made of the unadjusted and adjusted association between the number of chronic diseases, the number of 14 pre-selected diseases, and the presence of two or more chronic diseases (multiple morbidity) with adverse health events recorded.

RESULTS

Participants with a higher number of diseases (OR 1.11; 95% CI: 1.02-1.22), and 14 pre-selected diseases (OR 1.19; 95% CI: 1.03-1.38) had a higher adjusted mortality risk, but not a higher incident disease or mobility loss risk. Subjects with multiple morbidity had a higher non-significant mortality risk (HR 1.45; 95% CI: 0.87-2.43), than those without multiple morbidity. Disability-free mean time in participants with and without multiple morbidity was 846±34 and 731±17 days, respectively (Log-rank χ(2) 7.45. P=.006), and with our without mobility loss was 818±32 and 696±13 days, respectively (Log rank χ(2) 10.99. P=.001).

CONCLUSIONS

Multiple morbidity was not associated with mortality, incident disability in ADL, or mobility loss in adults older than 70 years, although if mortality is taken into account, the number of chronic diseases is linear.

Comorbidities are associated with poorer outcomes in community patients with rheumatoid arthritis

OBJECTIVE

To evaluate the impact of comorbidities on achieving remission by examining changes in the clinical disease activity index (CDAI) in RA patients in the community-based Consortium of Rheumatology Researchers of North America (CORRONA) registry.

METHODS

A subcohort of 1548 RA subjects with varying disease duration met the following inclusion criteria: started a DMARD/biologic agent, continued therapy ≥ 3 months, CDAI ≥ 2.8 at study entry and followed longitudinally from baseline to follow-up (mean time 7.46 months). Patients reported comorbidities according to a standardized list of 33 conditions. Entry characteristics were compared across age categories using one-way analysis of variance. Linear and logistic regression models were constructed to assess characteristics [e.g. age, disease duration, number of previous DMARDs/biologics, baseline modified health assessment questionnaire (MHAQ), baseline CDAI and number of comorbidities] associated with primary outcomes: change in CDAI (baseline to follow-up) and CDAI remission (yes/no).

RESULTS

Although disease activity measures at entry were similar across age categories, older patients had more comorbidities, less improvement in CDAI/MHAQ and were less likely to attain remission at follow-up. However, after adjusting covariates an increasing number of patient-reported comorbidities and higher baseline CDAI (but not age) were consistently and independently associated with a lower likelihood of clinical improvement or remission (P < 0.001).

CONCLUSION

In this observational cohort of community RA patients an increasing number of patients reported comorbidities, independently correlated with less CDAI improvement over time. These results reaffirm that comorbidities may be an important factor in consideration of treat-to-target recommendations and aid in understanding achievable RA therapeutic goals.

Research priorities in geriatric palliative care: multimorbidity

With global aging and scientific advances extending survival, the number of adults experiencing multiple chronic conditions has grown substantially and is projected to increase by another third between 2000 and 2030. Among the many challenges posed by multimorbidity, some of the most pressing include how to characterize and measure comorbid conditions, understand symptoms and illness burden, and provide person-centered care in the context of competing health care priorities and increasing complexity. In this white paper emanating from a National Institute on Aging supported conference to discuss research gaps at the geriatrics-palliative care interface, the authors review common definitions of multimorbidity; describe the association between multimorbidity and quality of life, functional status, quality of care, and health care utilization; note content and methodological gaps in multimorbidity evidence; and make recommendations regarding research priorities in this area of expanding public health impact.

Incremental Effects of Comorbidity on Quality of Life in Patients with Psoriatic Arthritis

Objective.

To assess the added effect of comorbidity on quality of life (QOL) in psoriatic arthritis (PsA).

Methods.

Between 2006 and 2012, 631 patients were recruited from the University of Toronto PsA Clinic. Using the clinical database, we ascertained the frequency of 15 comorbidities. The Medical Outcomes Study Short Form-36 (SF-36) physical (PCS) and mental component (MCS) summary scales were used to assess QOL. Linear regression analyses were conducted to estimate the magnitude of the association between number and type of comorbidities and PCS and MCS scores, after adjustment for disease-related and sociodemographic variables.

Results.

Prevalence of comorbidity was high, with 42% of patients having 3 or more comorbid conditions. After adjustment for inflammatory disease–related and sociodemographic factors, a history of 3 or more comorbid conditions accounted for only 2% and 1% of the R2 value explained in PCS and MCS scores, respectively. In terms of added burden, type of comorbid condition was more significant than number of comorbidities. After adjustment for disease-related and sociodemographic factors, fibromyalgia (FM), neurological disorders, and obesity jointly accounted for 6% of R2 value explained in PCS scores, while FM and depression/anxiety jointly accounted for about 9% of the R2 explained in MCS scores. The point decrease in PCS and MCS scores associated with each of these disorders was clinically significant. The 11 other comorbid conditions failed to achieve statistical significance in the models.

Conclusion.

The added effect of comorbidity on patient-reported physical and mental health in PsA was more related to type of comorbidity than number of comorbidities.

Multimorbidity in older adults

Multimorbidity, the coexistence of 2 or more chronic conditions, has become prevalent among older adults as mortality rates have declined and the population has aged. We examined population-based administrative claims data indicating specific health service delivery to nearly 31 million Medicare fee-for-service beneficiaries for 15 prevalent chronic conditions. A total of 67% had multimorbidity, which increased with age, from 50% for persons under age 65 years to 62% for those aged 65-74 years and 81.5% for those aged ≥85 years. A systematic review identified 16 other prevalence studies conducted in community samples that included older adults, with median prevalence of 63% and a mode of 67%. Prevalence differences between studies are probably due to methodological biases; no studies were comparable. Key methodological issues arise from elements of the case definition, including type and number of chronic conditions included, ascertainment methods, and source population. Standardized methods for measuring multimorbidity are needed to enable public health surveillance and prevention. Multimorbidity is associated with elevated risk of death, disability, poor functional status, poor quality of life, and adverse drug events. Additional research is needed to develop an understanding of causal pathways and to further develop and test potential clinical and population interventions targeting multimorbidity.

Neighborhood racial residential segregation and changes in health or death among older adults

We assessed relationships between neighborhood racial residential segregation (RRS), individual-level health declines and mortality using Health and Retirement Study data. We calculated the census-tract level Location Quotient for Racial Residential Segregation (LQRRS), and estimated adjusted relative risks (ARR) of LQRRS for declines in self-reported health or death 1992-2000, controlling for individual-level characteristics. Of 6653 adults, 3333 lived in minimal, 2242 in low, 562 in moderate, and 516 in high LQRRS tracts in 1992. Major decline/death rates were: 18.6%, 25.2%, 33.8% and 30.4% in minimal, low, moderate and high tracts, respectively. Adjusting for demographic characteristics, residence in low, moderate and high LQRRS census tracts was associated with greater likelihood of major decline/death compared to minimal LQRRS. Controlling for all variables, only moderate LQRRS predicted major decline/death, ARR=1.31 (95% CI 1.07, 1.59; p<.05).

Contributions of environment, comorbidity, and stage of dementia to the onset of walking and eating disability in long-term care residents

OBJECTIVES

To estimate the relative effects of environment, comorbidities, stage of dementia and other variables on disability onset.

DESIGN

A 1-year prospective cohort study was conducted in which the walking and eating abilities of long-term care residents were observed fortnightly. Structural equation modeling was used to assess the contributions of individual and environmental factors to the onset of disability.

SETTING

Fifteen nursing homes in western Canada.

PARTICIPANTS

One hundred twenty residents with middle-stage Alzheimer disease or related dementia.

MEASUREMENTS

Environmental quality was assessed using the Professional Environmental Assessment Protocol, comorbidity using the Charlson Comorbidity Index, and stage of dementia using the Global Deterioration Scale.

RESULTS

More-advanced baseline dementia had a direct effect on onset of walking and eating disability (standardized maximum likelihood estimate (SMLE) = 0.24, P = .006). Resident environment (SMLE = -0.25, P = .007) and comorbidities (SMLE = 0.32, P < .001) influenced disability onset approximately as strongly as stage of dementia. Smaller and publicly owned facilities provided superior environmental quality, which indirectly contributed to a delay in onset of walking and eating disability.

CONCLUSION

Environmental quality and extent of comorbidity are at least as important as progression of dementia in initiating or delaying the onset of disability.

Comorbidity and disease burden in the National Comorbidity Survey Replication (NCS-R)

BACKGROUND

Disease burden estimates rarely consider comorbidity. Using a recently developed methodology for integrating information about comorbidity into disease burden estimates, we examined the comparative burdens of nine mental and 10 chronic physical disorders in the National Comorbidity Survey Replication (NCS-R).

METHODS

Face-to-face interviews in a national household sample (n = 5,692) assessed associations of disorders with scores on a visual analog scale (VAS) of perceived health. Multiple regression analysis with interactions for comorbidity was used to estimate these associations. Simulation was used to estimate incremental disorder-specific effects adjusting for comorbidity.

RESULTS

The majority of respondents (74.9%) reported one or more disorders. Of respondents with disorders, 73.8-98.2% reported having at least one other disorder. The best-fitting model to predict VAS scores included disorder main effects and interactions for number of disorders. Adjustment for comorbidity reduced individual-level disorder-specific burden estimates substantially, but with considerable between-disorder variation (0.07-0.69 ratios of disorder-specific estimates with and without adjustment for comorbidity). Four of the five most burdensome disorders at the individual level were mental disorders based on bivariate analyses (panic/agoraphobia, bipolar disorder, posttraumatic stress disorder, major depression) but only two based on multivariate analyses, adjusting for comorbidity (panic/agoraphobia, major depression). Neurological disorders, chronic pain conditions, and diabetes were the other most burdensome individual-level disorders. Chronic pain conditions, cardiovascular disorders, arthritis, insomnia, and major depression were the most burdensome societal-level disorders.

CONCLUSIONS

Adjustments for comorbidity substantially influence estimates of disease burden, especially those of mental disorders, underlining the importance of including information about comorbidity in studies of mental disorders.

Chronic Condition Clusters and Polypharmacy among Adults

Objective. The primary objective of the study was to estimate the rates of polypharmacy among individuals with multimorbidity defined as chronic condition clusters and examine their associations with polypharmacy. Methods. Cross-sectional analysis of 10,528 individuals of age above 21, with at least one physical condition in cardiometabolic (diabetes or heart disease or hypertension), musculoskeletal (arthritis or osteoporosis), and respiratory (chronic obstructive pulmonary disease (COPD) or asthma) clusters from the 2009 Medical Expenditure Panel Survey. Chi-square tests and logistic regressions were performed to analyze the association between polypharmacy and multimorbidity. Results. Polypharmacy rates varied from a low of 7.2% among those with respiratory cluster to a high of 64.1% among those with all three disease clusters. Among those with two or more disease clusters, the rates varied from 28.3% for musculoskeletal and respiratory clusters to 41.8% for those with cardiometabolic and respiratory clusters. Individual with cardiometabolic conditions alone or in combination with other disease clusters were more likely to have polypharmacy. Compared to those with musculoskeletal and respiratory conditions, those with cardiometabolic and respiratory conditions had 1.68 times higher likelihood of polypharmacy. Conclusions. Rates of polypharmacy differed by specific disease clusters. Individuals with cardiometabolic condition were particularly at high risk of polypharmacy, suggesting greater surveillance for adverse drug interaction in this group.

Insomnia, comorbidity, and risk of injury among insured Americans: results from the America Insomnia Survey

STUDY OBJECTIVES

To estimate associations of broadly defined insomnia (i.e., meeting inclusion criteria for International Classification of Diseases, Tenth Revision (ICD-10), Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), or Research Diagnostic Criteria/International Classification of Sleep Disorders, Second Edition (RDC/ICSD-2) diagnosis) with workplace/nonworkplace injuries controlling for comorbid conditions among workers in the America Insomnia Survey (AIS).

DESIGN/SETTING

Cross-sectional telephone survey.

PARTICIPANTS

National sample of 4,991 employed health plan subscribers (age 18 yr and older).

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Broadly defined insomnia with duration of at least 12 mo was assessed with the Brief Insomnia Questionnaire (BIQ). Injuries in the 12 mo before interview were assessed with a standard self-report measure of injuries causing role impairment or requiring medical attention. Eighteen comorbid condition clusters were assessed with medical/pharmacy claims records and self-reports. Insomnia had significant gross associations (odds ratios, ORs) with both workplace and nonworkplace injuries (OR 2.0 and 1.5, respectively) in logistic regression analyses before controlling for comorbid conditions. The significant population attributable risk proportions (PARPs) of total injuries with insomnia was 4.6% after controlling for comorbid conditions. Only 2 other conditions had PARPs exceeding those of insomnia. The associations of insomnia with injuries did not vary significantly with worker age, sex, or education, but did vary significantly with comorbid conditions. Specifically, insomnia was significantly associated with workplace and nonworkplace injuries (OR 1.8 and 1.5, respectively) among workers having no comorbid conditions, with workplace but not nonworkplace injuries (OR 1.8 and 1.2, respectively) among workers having 1 comorbid condition, and with neither workplace nor nonworkplace injuries (OR 0.9 and 1.0, respectively) among workers having 2 or more comorbid conditions.

CONCLUSIONS

The associations of insomnia with injuries vary with comorbid conditions in ways that could have important implications for targeting workplace interventions.

Patterns of multimorbidity in primary care patients at high risk of future hospitalization

Care management is seen as a promising approach to address the complex care needs of patients with multimorbidity. Predictive modeling based on insurance claims data is an emerging concept to identify patients likely to benefit from care management interventions. We aimed to identify and explore patterns of multimorbidity in primary care patients with high predicted risk of future hospitalizations in order to develop a primary care-based care management intervention. We conducted a retrospective cohort study to assess insurance claims data of 6026 patients from 10 primary care practices in Germany. We stratified the population by the predicted likelihood of hospitalization (LOH) using a diagnostic cost group-based case-finding software. Co-occurrence of chronic conditions in multimorbid patients with an upper-quartile LOH score was explored by extraction of mutually exclusive patterns. Predictive modeling identified multimorbid elderly patients with a high number of co-occurring chronic conditions (mean number 7.8 [SD 3.1]). Assessing co-occurrence of highly prevalent chronic conditions in 1407 multimorbid patients with upper-quartile LOH revealed 471 mutually exclusive patterns with low single frequencies. The observed prevalence significantly exceeded expected prevalence for patterns with causal comorbidity. Additionally, chronic pain (related to osteoarthritis) or depression could be identified as discordant co-occurring conditions in 80% (12/15) of the most common multimorbidity patterns. High-risk primary care patients suffer from heterogeneous individual patterns of co-occurring chronic conditions. Care management interventions will have to account for discordant co-occurring conditions such as osteoarthritis and depression.

Patterns of multimorbidity in the aged population. Results from the KORA-Age study

Multimorbidity is a common problem in aged populations with a wide range of individual and societal consequences. The objective of the study was to explore patterns of comorbidity and multimorbidity in an elderly population using different analytical approaches. Data were gathered from the population-based KORA-Age project, which included 4,127 persons aged 65–94 years living in the city of Augsburg and its two surrounding counties in Southern Germany. Information on the presence of 13 chronic conditions was collected in a standardized telephone interview and a self-administered questionnaire. Patterns of comorbidity and multimorbidity were analyzed using prevalence figures, logistic regression models and exploratory tetrachoric factor analysis. The prevalence of multimorbidity (≥2 diseases) was 58.6% in the total sample. Hypertension and diabetes (Odds Ratio [OR] 2.95, 99.58% confidence interval [CI] [2.19–3.96]), as well as hypertension and stroke (OR 2.00, 99.58% CI [1.26–3.16]) most often occurred in combination. This association was independent of age, sex and the presence of other conditions. Using factor analysis, we identified four patterns of multimorbidity: the first pattern includes cardiovascular and metabolic diseases, the second includes joint, liver, lung and eye diseases, the third covers mental and neurologic diseases and the fourth pattern includes gastrointestinal diseases and cancer. 44% of the persons were assigned to at least one of the four multimorbidity patterns; 14% could be assigned to both the cardiovascular/metabolic and the joint/liver/lung/eye pattern. Further common pairs were the mental/neurologic pattern combined with the cardiovascular/metabolic pattern (7.2%) or the joint/liver/lung/eye pattern (5.3%), respectively. Our results confirmed the existence of co-occurrence of certain diseases in elderly persons, which is not caused by chance. Some of the identified patterns of multimorbidity and their overlap may indicate common underlying pathological mechanisms.

Health and social services integration: a review of concepts and models

Health and social services integration is particularly relevant for populations whose needs span physical health, mental health, housing, and disability services, along with others. Veterans, homeless, chronically ill, and aging are among those populations. This review examines recent peer-reviewed literature about different approaches to services integration, rationales behind those approaches, and successes of those approaches, including factors that make them succeed or fail. The focus here is on services that cross disciplinary boundaries; that is, those that integrate health services with social services, health services with mental health services, or one social service with a categorically different social service.

Prevalence of disability according to multimorbidity and disease clustering: a population-based study

Background

The prevalence of chronic diseases has increased with population ageing, and research has attempted to elucidate the correlation between chronic diseases and disability. However, most studies in older populations have focused on the effect of single disabling conditions, even though most older adults have more than one chronic disease (multimorbidity).

Objective

The aims of this study were to evaluate the association of disability with disease, in terms of multimorbidity and specified pairs of diseases, in a population-based study of older adults. Materials and Methods: Using the Kungsholmen Project, we estimated the prevalence of disability by the number of chronic diseases, disease status by organ systems, and in specific pairs of chronic conditions, in a Swedish population (n=1,099; ≥77 years). Disability was defined as need of assistance in at least one activity of daily living (Katz index).

Results

Functional disability was seen in 17.9% of participants. It increased as the number of chronic diseases increased. The prevalence of disability varied greatly amongst specific pairs of diseases: from 6.7% in persons affected by hypertension and atrial fibrillation to 82.4% in persons affected by dementia and hip fracture. In multivariate logistic regression models, the disease pairs that were significantly associated with the highest increased relative odds of disability contained dementia (dementia–hip fracture, dementia–CVD, and dementia–depression).

Conclusions

Our findings suggest specific pairs of diseases are much more highly associated with disability than others, particularly diseases coupled with dementia. This knowledge may improve prevention of disablement and planning of resource distribution.

Journal of Comorbidity 2011;1:11–18

How does the trajectory of multimorbidity vary across Black, White, and Mexican Americans in middle and old age?

OBJECTIVES

This research examines intra- and interpersonal differences in multiple chronic conditions reported by Americans aged 51 and older for a period up to 11 years. It focuses on how changes in multimorbidity vary across White, Black, and Mexican Americans.

METHODS

Data came from 17,517 respondents of the Health and Retirement Study (1995-2006) with up to 5 repeated observations. Hierarchical linear models were employed to analyze ethnic variations in temporal changes of reported comorbidities.

FINDINGS

Middle-aged and older Americans have on average nearly 2 chronic diseases at the baseline, which increased to almost 3 conditions in 11 years. White Americans differ from Black and Mexican Americans in terms of level and rate of change of multimorbidity. Mexican Americans demonstrate lower initial levels and slower accumulation of comorbidities relative to Whites. In contrast, Blacks showed an elevated level of multimorbidity throughout the 11-year period of observation, although their rate of change slowed relative to Whites.

DISCUSSION

These results suggest that health differences between Black Americans and other ethnic groups including White and Mexican Americans persist in the trajectory of multimorbidity even when population heterogeneity is adjusted. Further research is needed concerning the impact of health disadvantages and differential mortality that may have occurred before middle age as well as exploring the role of nativity, the nature of self-reported diseases, and heterogeneity underlying the average trajectory of multimorbidity for ethnic elders.

Correlates of mobility limitation in African Americans

BACKGROUND

This study identified demographic and health-related characteristics that were related to mobility limitation in a sample of community-dwelling African Americans.

METHODS

The sample consisted of 602 community-dwelling African-American men and women ages 48-92 years at study inception. Participants who reported being limited "a lot" or "a little" in climbing one flight of stairs or walking several blocks were considered to have mobility limitation. Logistic regression was conducted to estimate the independent effect of each demographic and health-related characteristic on odds of mobility limitation.

RESULTS

African Americans who reported two or more medical conditions had higher odds of mobility limitation (women: odds ratio = 3.52; 95% confidence interval: 1.89-6.53 and men: odds ratio = 2.53; 95% confidence interval: 1.10-5.85) than those who reported one or fewer medical conditions. African Americans with major depressive symptoms had higher odds of mobility limitation (women: odds ratio = 2.98; 95% confidence interval: 1.55-5.71 and men: odds ratio = 3.19; 95% confidence interval: 1.33-7.65) than those without major depressive symptoms.

CONCLUSIONS

These results highlight the importance of creating interventions particularly focused on chronic disease prevention and management for African American men and women during midlife to attempt to delay the onset or impede the progression of mobility problems that will likely become exacerbated in late life and severely affect the quality of life.

Including information about co-morbidity in estimates of disease burden: results from the World Health Organization World Mental Health Surveys

BACKGROUND

The methodology commonly used to estimate disease burden, featuring ratings of severity of individual conditions, has been criticized for ignoring co-morbidity. A methodology that addresses this problem is proposed and illustrated here with data from the World Health Organization World Mental Health Surveys. Although the analysis is based on self-reports about one's own conditions in a community survey, the logic applies equally well to analysis of hypothetical vignettes describing co-morbid condition profiles.

METHOD

Face-to-face interviews in 13 countries (six developing, nine developed; n=31 067; response rate=69.6%) assessed 10 classes of chronic physical and nine of mental conditions. A visual analog scale (VAS) was used to assess overall perceived health. Multiple regression analysis with interactions for co-morbidity was used to estimate associations of conditions with VAS. Simulation was used to estimate condition-specific effects.

RESULTS

The best-fitting model included condition main effects and interactions of types by numbers of conditions. Neurological conditions, insomnia and major depression were rated most severe. Adjustment for co-morbidity reduced condition-specific estimates with substantial between-condition variation (0.24-0.70 ratios of condition-specific estimates with and without adjustment for co-morbidity). The societal-level burden rankings were quite different from the individual-level rankings, with the highest societal-level rankings associated with conditions having high prevalence rather than high individual-level severity.

CONCLUSIONS

Plausible estimates of disorder-specific effects on VAS can be obtained using methods that adjust for co-morbidity. These adjustments substantially influence condition-specific ratings.