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Geriatr Gerontol Int 2016
REVIEW ARTICLE
Prevalence of sarcopenia in older Brazilians: A systematic review and meta-analysis Juliano Bergamaschine Mata Diz,1 Amanda Aparecida Oliveira Leopoldino,1,2 Bruno de Souza Moreira,1 Nicholas Henschke,3 Rosangela Correa Dias,1 Leani Souza Máximo Pereira1 and Vinicius Cunha Oliveira1 1
Postgraduate Program in Rehabilitation Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; 2The George Institute for Global Health, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia; and 3Institute of Public Health, University of Heidelberg, Heidelberg, Germany
Aim: Sarcopenia is the age-related loss of muscle mass and function that evolves into disability, loss of independence and death. In Brazil the number of older people is rapidly growing, resulting in an increased prevalence of chronic conditions associated with old age. As prevalence estimates provide essential information to policymakers when developing healthcare strategies, this systematic review and meta-analysis aimed to estimate the prevalence of sarcopenia in older Brazilians. Methods: Electronic database searches and hand-searching in relevant journals and reference lists were carried out without language restriction. Studies that reported the prevalence of sarcopenia in Brazilians aged 60 years or older were considered for inclusion. Sarcopenia was defined as low muscle mass, low muscle function or low muscle mass and function. Meta-analysis was carried out using a random-effects model. Results: A total of 31 studies were included pooling 9416 participants. The overall prevalence of sarcopenia in older Brazilians was 17.0% (95% CI 13.0–22.0). Sensitivity analysis showed rates of 20.0% (95% CI 11.0–32.0) in women and 12.0% (95% CI 9.0–16.0) in men. Prevalence was 16.0% (95% CI 12.0–23.0) based on low muscle mass and function; and 17.0% (95% CI 9.0–31.0) based only on low muscle mass. The difference between these two criteria was not significant (P = 0.96). Conclusions: Sarcopenia is an emerging public health issue in Brazil. Attention should be paid to changes in prevalence rates over the next years because of the increase in the older population. Geriatr Gerontol Int 2016; ••: ••–••. Key words: age-related muscle loss, epidemiology, meta-analysis, prevalence, public health.
Introduction In a time where the world’s population is aging at an unprecedented rate, one of the most important challenges in the healthcare field is to slow the decline of the musculoskeletal system.1,2 In this regard, age-related loss of muscle mass and function (i.e. strength and physical performance), or sarcopenia, is an intrinsic
Accepted for publication 26 November 2015. Correspondence: Mr Juliano Bergamaschine Mata Diz MSc, Departamento de Fisioterapia, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais 31270-901, Brasil. Email:
[email protected]
© 2016 Japan Geriatrics Society
manifestation of the aging process, which can have severe implications on the functionality of older people.2 Sarcopenia is the essential component of frailty syndrome, and has been strongly associated with poor health outcomes, such as disability, morbidity and mortality.3–5 The burden of this condition is extensive, and is increasing rapidly as a result of the fast increase in older populations.6,7 After 50 years-of-age, following the process of fat accumulation as a substitution to lean body mass, it is estimated that muscle mass decreases consistently at a rate of approximately 1.0% per year, whereas gait speed and grip strength decrease at a rate of 2.0–2.2% and 1.9–5.0% per year, respectively.8,9 In the USA, estimates calculated from national prevalence data showed that in the year 2000, 45.0% of the older population had sarcopenia, and their risk of disability was doi: 10.1111/ggi.12720
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1.5–4.6-fold higher than those classified as having normal muscle mass.6 The direct cost of sarcopenia was estimated at more than US$18 billion, representing 1.5% of the total healthcare expenditure of the year 2000.6 Nationwide surveys with large samples have been carried out in high-income countries to identify sarcopenia in the older population; however, this has not yet been carried out in low- and middle-income countries.10–12 In Brazil, it is estimated that 700 000 people aged ≥60 years are added to the population every year, and the country has the sixth largest number of older people in the world.13 Currently, there are approximately 23.5 million older Brazilians, representing 12.6% of the total population in Brazil, and it is expected an increase of over 8.5 million by 2025, when this population will represent 15.0% of the total.14 As a result, Brazil is experiencing a substantial increase in the frequency of age-related chronic conditions and their negative consequences.15 As prevalence information is a vital first step when planning healthcare strategies geared to the older population, the present systematic review estimated the prevalence of sarcopenia in older Brazilians from nationwide pooled estimates. To our knowledge, this is the first meta-analysis pooling prevalence of sarcopenia in older people.
Methods The protocol of the present review is registered at PROSPERO (CRD42015020344).16 Methods were based on recommendations from the Joanna Briggs Institute Reviewers’ Manual (The Systematic Review of Prevalence and Incidence Data),17 the Cochrane Collaboration18 and MOOSE (Meta-analysis of Observational Studies in Epidemiology) reporting guidelines.19
Search strategy This review searched the following databases from the earliest record to May 2015: MEDLINE, AMED, CINAHL, EMBASE, LILACS and SciELO, without language restriction. Additionally, hand-searching was carried out in relevant journals and reference lists of eligible studies, and Brazilian experts in the field were consulted to identify any important studies. The search strategy using English descriptors related to “prevalence,” “epidemiology,” “sarcopenia,” “older people,” “Brazil” and their variations is described in Appendix S1.
Inclusion criteria Studies investigating the prevalence of sarcopenia in older Brazilians aged 60 years or older from community, 2
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clinical/hospital and long-term care settings were considered for inclusion. The sample size was not fixed in order to retrieve a large number of studies for inclusion. Sarcopenia was defined as low muscle mass,20 low muscle function21 or low muscle mass plus low muscle function22 identified by validated diagnostic criteria commonly used in previous clinical or epidemiological studies as follows. Muscle mass: magnetic resonance imaging, computed tomography, dual-energy X-ray absorptiometry (DEXA), bioelectrical impedance or anthropometry. Muscle function: (i) strength: handgrip and knee extension/flexion strength tests; and (ii) physical performance: components of the Short Physical Performance Battery and Timed Up & Go test.23 Studies on the prevalence of sarcopenia within already diagnosed medical conditions (such as cancer, diabetes or chronic kidney disease) were excluded. Furthermore, other subclassifications, such as moderate and severe sarcopenia, were not used.
Study selection After assessing titles and abstracts retrieved from the searches, potential full-texts were assessed for eligibility by two independent reviewers (JBMD and AAOL). Those studies fulfilling the eligibility criteria were included. When two studies used the same sample, the one with largest sample size was included.
Data extraction and quality assessment Data were extracted by two independent reviewers (JBMD and AAOL), and disagreements were resolved by consensus. Extracted data included details on the study design, setting, participants, diagnostic criteria and prevalence. Two studies24,25 estimated the prevalence of sarcopenia using two different criteria to measure muscle mass, and we chose to extract the prevalence rate obtained from the criterion most similar to other included studies (i.e. Baumgartner’s criteria).26 One study estimated the prevalence of sarcopenia from several criteria;27 in this case, we chose to extract the prevalence rate given by the most complete criterion, comprising Baumgartner’s criteria to rank muscle mass combined with measures of muscle function as recommended by the European Working Group on Sarcopenia in Older People (EWGSOP).28 In two studies, to clarify data on mean age29,30 and sex,30 authors were contacted; however, they did not answer our request. Thus, we used a hot deck imputation method, selecting a value randomly from the other studies carried out in the same setting.31 Two reviewers (JBMD and BSM) also independently assessed risk of bias for each included study using a validated tool that has 10 items that provide methodological quality assessment of prevalence studies.32 A third reviewer (VCO) solved potential disagreements. © 2016 Japan Geriatrics Society
Prevalence of sarcopenia in Brazil
Statistical analysis Descriptive statistics were used to first describe the extracted data. Prevalence rates were managed as a logit event estimate to normalize the distribution of data. Logit event estimates were then back-transformed into proportions with 95% CI when pooled analysis was carried out. The overall prevalence rates were reported in percentages.17 Meta-analysis was carried out according to the I2 statistic considering low heterogeneity when I2 < 50% and moderate to high heterogeneity when I2 ≥ 50%.18 Pooled effects were estimated using fixed-effect model when I2 < 50% or using a random-effects model when I2 ≥ 50%. Meta-analysis was not reported if I2 remained ≥ 50%, even after using a random-effects model. In this case, data were descriptively analyzed. A funnel plot of precision by logit event rate was used to investigate publication bias, and Begg–Mazumdar and Egger’s tests were used to assess the significance of funnel plot asymmetry.18 Sensitivity analysis investigated the impact of the following factors that could influence the prevalence of sarcopenia: the presence of extreme values (considering values of prevalence greater than previously reported, i.e. range > 50.0%);33,34 diagnostic criteria (sarcopenia identified by measuring muscle mass and function as recommended by the EWGSOP28 vs others, and sarcopenia identified only by measuring muscle mass using DEXA and Baumgartner’s criteria vs others); sex; age group (
