Comparison of respiratory muscle strength between fragility subgroups in community elderly

Abstracts

A fragilidade é composta por um tripé constituído por: sarcopenia, disfunção imunológica e desregulação neuroendócrina. A sarcopenia é definida como uma diminuição na força e na potência muscular, sendo que os músculos respiratórios também são afetados. O objetivo foi comparar a força muscular respiratória (FMR) em idosas residentes na comunidade, classificadas como não frágeis (NF), pré-frágeis (PF) e frágeis (F) e correlacionar a FMR com a força de preensão manual (FPM). O estudo foi do tipo transversal, com uma amostra de conveniência composta por 106 idosas. As participantes foram classificadas quanto ao fenótipo de fragilidade. A FMR foi avaliada por meio da pressão inspiratória máxima (PImáx) e da pressão expiratória máxima (PEmáx). Foram encontradas diferenças significativas da FMR entre os grupos NF e F (PImáx: p=0,001 e PEmáx: p<0,001) e entre os grupos PF e F (PImáx: p<0,001 e PEmáx: p<0,001). Em relação à FPM, foram observadas diferenças significativas entre todos os grupos (p<0,001). Houve correlação entre FMR e FPM apenas no grupo frágil. Desta forma, a FPM pode ser importante na prática clínica para diferenciar os subgrupos de fragilidade e identificar a perda de força muscular, incluindo a perda da FMR.

Idoso Fragilizado; Força Muscular; Sistema Respiratório; Idoso

ORIGINAL RESEARCH

Adriana Netto Parentoni^I; Lygia Paccini Lustosa^II; Karla Doriane dos Santos^III; Luiz Fernando Sá^III; Fernanda Oliveira Ferreira^IV; Vanessa Amaral Mendonça^I

^IPhysical Therapy Department of UFVJM - Diamantina (MG), Brazil

^IIPhysical Therapy Department of Universidade Federal de Minas Gerais (UFMG) - Belo Horizonte (MG), Brazil

^IIIPhysical Therapy program at UFVJM - Diamantina (MG), Brazil

^IVBasic Sciences Department of UFVJM - Diamantina (MG), Brazil

Correpsondence to

ABSTRACT

The fragility consist in a tripod comprising: sarcopenia, immune dysregulation, and neuroendocrine dysfunction. Sarcopenia is defined as a decrease in strength and muscle power, so that the respiratory muscles are also affected. The aim was to compare respiratory muscle strength (RMS) in elderly community residents, classified as nonfrail (NF), pre frail (PF) and frail (F), and correlate RMS with the handgrip strength (HS). The study was cross-sectional, with a convenience sample of 106 elderly women. Participants were classified according to the phenotype of frailty. The RMS was assessed by maximal inspiratory pressure (MIP) and maximum expiratory pressure (MEP). Significant differences were found in RMS between groups NF and F (MIP: p=0.001 and MEP: p<0.001) and between groups PF and F (MIP: p<0.001 and MEP: p<0.001). In relation to HS, significant differences were observed between all groups (p<0.001). There was correlation between HS and RMS only in the frail group. Thus, the HS may be important in the clinical evaluation to differentiate subgroups of fragility and identify the loss of muscle strength, including the loss of RMS.

Keywords: Frail Elderly; Muscle Strength; Respiratory System; Aged.

RESUMEN

La fragilidad está compuesta por un trípode constituido por: sarcopenia, disfunción inmunológica y desregulación neuroendócrina. La sarcopenia es definida como una disminución de la fuerza y de la potencia muscular, donde los músculos respiratorios también son afectados. El objetivo fue comparar la fuerza muscular respiratoria (FMR) en añosas residentes en la comunidad, clasificadas como no frágiles (NF), pre-frágiles (PF) y frágiles (F) y correlacionar la FMR con la fuerza de prensión manual (FPM). El estudio fue del tipo transversal, con una muestra de conveniencia compuesta por 106 añosas. Las participantes fueron clasificadas en cuanto al fenotipo de fragilidad. La FMR fue evaluada por medio de la presión inspiratoria máxima (PImáx) y de la presión expiratoria máxima (PEmáx). Fueron encontradas diferencias significativas de la FMR entre los grupos NF y F (PImáx: p=0,001 y PEmáx: p<0,001) y entre los grupos PF y F (PImáx: p<0,001 y PEmáx: p<0,001). En relación a la FPM, fueron observadas diferencias significativas entre todos los grupos (p<0,001). Hubo correlación entre FMR y FPM apenas en el grupo frágil. De esta forma, la FPM puede ser importante en la práctica clínica para diferenciar los subgrupos de fragilidad e identificar la pérdida de fuerza muscular, incluyendo la pérdida de la FMR.

Palabras clave: Anciano Frágil; Fuerza Muscular; Sistema Respiratorio; Anciano.

INTRODUCTION

The aging process is characterized by physiological alterations that compromise various organs and systems, culminating in functional decline¹. In this context, the phenomenon "frailty", attributed to elderly people, can be defined as a clinical state of greater vulnerability consequential of a decline in the reserve and function of multiple physiological systems^2,3.

Fried et al.² consider five criteria to detect frailty syndrome: self-report of exhaustion, low gait speed (GS), weakness assessed through handgrip strength (HGS), involuntary weight loss greater or equal to 4.5 kg or 5% in the past year, and low level of physical activity, measured through weekly energy expenditure^2,4. Three or more of these criteria must be clinically present to classify an elderly individual as frail (F); when one or two factors exist, this elderly person is considered pre frail (PF), and when none of these criteria is detected, he/she can be classified as non frail (NF)².

The tripod that composes the main physiological alterations associated with the frailty syndrome comprises immune dysfunction, neuroendocrine dysregulation and sarcopenia^2,5; the latter is considered a central component⁵.

In this context of frailty syndrome, sarcopenia is the alteration most commonly observed in the muscles as ageing progresses⁶, and it is the main factor that contributes to the loss of functional mobility and independence in many elderly people⁷. It is defined as a decrease in muscle strength and power due to the atrophy of muscle fibers⁶.

This decline in strength has also been documented in respiratory muscles^8,9. In this case, it can lead to a decrease in pulmonary functioning and inadequate energy supply, which can affect the strength of lower limbs (LL), thus contributing to the development of functional incapacity¹⁰. However, it is known that respiratory muscle strength (RMS) is related to a decrease in mobility in elderly people, regardless of the level of physical activity and LL strength¹¹, and that HGS has been considered one of the best predictors of the loss of overall muscle strength¹².

In light of this, the aim of this study was to compare the RMS of elderly women who reside in the community, classified as NF, PF and F, and to verify the correlation between RMS and HGS.

METHODOLOGY

Sample

This is a transversal study conducted with a convenience sample composed of 106 female volunteers recruited through the registers of four Family Health Strategies in the city of Diamantina, Minas Gerais. The study was approved by UFVJM's Research Ethics Committee, report number 056/11. All volunteers signed the Free and Informed Consent.

We included female elderly individuals > 65 years of age. We excluded elderly women whose Mini Mental State Exam (MMSE) scores were incompatible with their schooling; those unable to roam without mechanical or human help; those with neurological illnesses; individuals who had been hospitalized less than three months prior to the study; those who had fractures acquired less than six months before; those with acute musculoskeletal impairment and/or decompensated respiratory or cardiovascular illnesses; those who were unable to perform the actions required to measure RMS and HGS; individuals who were taking digoxin, due to its positive influence on RMS¹³; and those who refused to participate in the study.

Procedures

The elderly women were submitted to previously scheduled individual assessments, and all collections were performed in the afternoon at an adequate location in the community. Initially, they answered a questionnaire in order to ensure the inclusion criteria. Then, their body weight and height were measured and the body mass index (BMI=height/weight²)¹⁴ was calculated. Lastly, they were submitted to the application of the five criteria proposed by Fried et al.^II; in order to be classified as NF, PF or F, in addition to having their respiratory pressure measured.

Classification of Frailty Phenotypes

For the purposes of classifying the frailty phenotypes, we assessed the five criteria proposed by Fried et al.²; namely:

• Self-reported unintended weight loss in the past year (4.5 kg or 5% of body weight);

• The HGS was measured with the use of a duly calibrated SH5001 - SAEHAN hydraulic hand dynamometer. Three measurements were taken from the dominant hand with 60-second intervals between each measurement. We considered the average of these measurements, adjusted in regards to sex and BMI^2,15. The position adopted for the conduction of this procedure was recommended by the American Society of Hand Therapists, and the standardized verbal stimulus was "Squeeze as hard as possible"¹⁵.

• The self-report of exhaustion was assessed by means of two statements from the CES-D questionnaire of depressive symptoms: "I felt that I had to make an effort to handle routinely tasks", and "I could not carry my things forward"^2,16.

• In order to assess GS, we used a stopwatch to track the time taken by the volunteers, in seconds, to walk for 4,6 meters at their usual speed. We considered the best performance out of two attempts^2,17.

• The level of physical activity was measured through low weekly energy expenditures in kcal, obtained by applying the Brazilian Portuguese version of the Minnesota Leisure Time Activities Questionnaire¹⁸. We evaluated the activities performed during the two weeks prior to the evaluation. We considered a weekly expenditure <270 kcal as low weekly energy expenditure².

Assessment of respiratory muscle strength

RMS was assessed by measuring the maximal inspiratory pressure (MIP) and the maximal expiratory pressure (MEP) using a hand vacuum pump, model MV-150/300, manufactured by Ger-Ar Comércio e Equipamentos Ltda^®.

Each volunteer was seated with her feet supported and her nose occluded with a nasal clip. The maneuvers were repeated up to five times. We collected three acceptable maneuvers and the maximal respiratory efforts that were sustained for at least two seconds¹⁹. We considered acceptable the measurements without air leaks and with a variation<10% than the highest value detected. The sequence of MIP and MEP measurements was random, and the highest measurement was selected for analysis^19,20.

The MIP was measured based on the residual volume, and the MEP on total lung capacity. An interval of at least one minute was established between each MIP and MEP measurement so as to allow the participant to recover^19,20. In order to precise the interval between MIP and MEP collection, we observed the normalization of O₂ saturation and the return of systemic blood pressure to basal levels.

Statistical Analysis

We conducted a pilot study with ten volunteers using the Intraclass Correlation Coefficient (ICC) with the purpose of assessing the reliability of the measurements between two evaluators. ICC values that varied between 0.69 and 1.00 revealed an adequate intra- and inter-examiner concordance for all measurements (RMS, HGS, GS, and Minnesota Leisure Time Activities Questionnaire).

The sample calculation for the comparison of quantitative variables among the groups²¹ considered a 95% confidence interval (95%CI) and indicated the necessity of allocating 31 elderly women in each group.

For data analysis, we used the statistical package SPSS, version 14, and adopted a significance level of 5%. Through Kolmogorov-Smirnov's test, we verified that only the data concerning the variables BMI and HGS presented normal distribution; thus, we used the one-way ANOVA to compare them among the three groups. The comparison of the variables RMS, age, weight and height in the three groups was conducted by means of Kruskal-Wallis' test, given that the distribution in this case was not normal. In order to investigate the differences between each of the groups, we relied on paired comparisons (NF x PF; NF x F; PF x F), using Bonferroni's test for HGS and Mann-Whitney's test for RMS and age. We utilized Spearman's correlation analysis to evaluate the correlation between HGS and RMS.

RESULTS

We evaluated 113 elderly women with age average of 73.96±6.91 years (varying between 65 and 91 years of age). Seven volunteers were excluded from the study: three due to the use of digoxin, two because of MMSE scores incompatible with their schooling, and two because they were unable to participate in the tests. In the end, we included 106 volunteers in the study who, after the classification of their frailty phenotype, were divided in three groups: 32 were considered NF, 42 were PF, and 32 were F.

The characterization of the sample is presented on Table 1. There was a significant difference in age between the groups NF and F (p=0.001), and PF and F (p=0.001), which demonstrates that F elderly women are older. Regarding weight, height and BMI, we did not find significant differences among the groups.

Figure 1 displays the median values of the variables MIP and MEP by group. There was a significant difference (p<0.001) in relation to RMS when the three groups were compared (NF, PF and F). After the paired comparison of RMS between the groups, we did not find significant differences between NF and PF (MIP: p=0.723 and MPE: p=0.118), but we verified significant differences between the groups NF and F (MIP: p=0.001 and MEP: p<0.001), and between the groups PF and F (MIP: p<0.001 and MEP: p<0.001).

Regarding HGS, the average values are presented by group on Figure 2. There were significant differences among the three groups (p<0.001) and also when comparing them pair by pair (p<0.001), which demonstrates that the F elderly women had lower HGS than the other groups, and that the PF participants had lower HGS than those in the NF group.

The statistical power found for the correlation between MIP and HGS was higher than 86%, and it surpassed 90% between MEP and HGS. We found moderate significant correlations between HGS and MIP (r=0.303) and MEP (r=0.386) when we considered the analysis with all participants. In the analysis by group, only the F elderly women presented a significant correlation between HGS and RMS, as it is shown on Table 2.

DISCUSSION

This study had the purpose of comparing RMS in elderly women of the community, classified as NF, PF and F, and correlating RMS and HGS. In the present study, group F presented statistically lower values of MIP, MEP and HGS when compared to the NF and PF groups, and it also had positive significant correlations among these variables. We also found lower HGS values in the PF group when compared to the NF group.

Simões et al.²² found negative correlations between age and RMS, which reinforces the results of this study. Moreover, some studies have demonstrated a relation between ageing and frailty⁵, which is also in accordance with the present study, since we found that the frail elderly participants were older. Therefore, we believe that these two factors, older age and lower RMS, can contribute to a higher risk of functional incapacity, and these individuals have higher chances of experiencing adverse health effects, as it is shown in the literature^2,5.

Moreover, some authors point out that the main factor that contributes to frailty and loss of functional mobility is skeletal muscle atrophy associated with weakness, which are characteristic of sarcopenia⁷. This decline in strength can be assessed through HGS measurement, which, in addition to predicting a reduction in overall muscle strength¹², can indicate functionality limitations²³, life quality²⁴, mortality²⁵, and fast decay of daily life activities and cognition²⁶.

In this case, the HGS decline found in the present study can be an indirect indicator of functional limitations and of a greater need for care for these individuals. However, since the aim of this study was not to assess functional losses, this might be a limitation that must be investigated in future studies. Nevertheless, the decrease in HGS observed in elderly people can be used to suggest more adequate strategies of prevention and health measures, given that these measures can be fundamental in delaying the loss of muscle mass consequential of ageing, and thus promote a smaller impact on the life quality of these elderly women^27,28.

Likewise, the training of respiratory muscles increases the benefits of aerobic exercises and it can be an alternative to those who have no conditions to perform this exercise⁸. Weiss et al.²⁹ have demonstrated that frail elderly women suffer a decrease in their capacity to practice exercises as well as compromising of lung functioning, which can suggest RMS decrease. Therefore, based on the literature, it is possible to infer that RMS is an important physiological variable that helps to prevent functional decline^8,30.

In addition, authors have pointed out the necessity of actions that have the purpose of strengthening respiratory muscles in elderly people in order to reduce mortality, given that RMS can explain the association between mortality and the muscle strength of body extremities²⁵. In this sense, the fact that RMS is related to HGS reinforces the use of the latter in clinical practice.

It is worth highlighting that the recruitment of elderly women from different locations enabled us to obtain data that portray more accurately the diversity of residents of the community in question.

To our knowledge, there are no studies in the literature that correlate RMS and HGS. In a study carried out by Buchman et al.²⁵, the authors concluded that the measurement of the muscle strength of the extremities can replace RMS. Therefore, the positive association found in this study between RMS and HGS suggests that the latter can be useful in clinical practice when inferring about the RMS of frail elderly women, given that the measurement of RMS requires greater cognitive capacity in understanding the commands. Moreover, some authors have affirmed that HGS loss is a sign of frailty and it can be used as a single marker of frailty³¹.

CONCLUSION

The results of this study demonstrate that frail elderly women suffer significant RMS and HGS losses. Likewise, we observed that a decline in HGS begins to appear already in the preceding stage, that is, when these people are classified as pre frail. Therefore, HGS, which is a simple and easily applicable measurement, can be an important factor to differentiate frailty subgroups and identify muscle strength loss, including RSM loss, in clinical assessment.

REFERENCES

• 1. Britto RR, Zampa CC, Oliveira TA, Prado LF, Parreira VF. Effects of the aging process on respiratory function. Gerontology. 2009;55(5):505-10.
• 2. Fried LP, Tangen CM, Walston J, Newman AB, Hirsch C, Gottdiener J. Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 2001;56(3):146-56.
• 3. Xue QL. The frailty syndrome: definition and natural history. Clin Geriatr Med. 2011;27(1):1-15.
• 4. Fedarko NS. The biology of aging and frailty. Clin Geriatr Med. 2011;27(1):27-37.
• 5. Espinoza SE, Fried LP. Risk factors for frailty in the older adult. Clin Geriatr. 2007;15(6):37-44.
• 6. Kim J, Sapienza CM. Implications of expiratory muscle strength training for rehabilitation of the elderly: Tutorial. J Rehabil Res Dev. 2005;42(2):211-24.
• 7. von Haehling S, Morley JE, Anker SD. An overview of sarcopenia: facts and numbers on prevalence and clinical impact. J Cachexia Sarcopenia Muscle. 2010;1(2):129-33.
• 8. Cebrià I Iranzo MD, Arnall DA, Camacho CI, Tomás JM, Meléndez JC. Physiotherapy intervention for preventing the respiratory muscle deterioration in institutionalized older women with functional impairment. Arch Bronconeumol. 2013;49(1):1-9.
• 9. Summerhill EM, Angov N, Garber C, McCooL FD. Respiratory muscle strength in the physically active elderly. Lung. 2007;185(6):315-20.
• 10. Buchman AS, Boyle PA, Leurgans SE, Evans DA, Bennett DA. Pulmonary function, muscle strength, and incident mobility disability in elders. Proc Am Thorac Soc. 2009;6(7):581-7.
• 11. Buchman AS, Boyle PA, Wilson RS, Leurgans S, Shah RC, Bennett DA. Respiratory muscle strength predicts decline in mobility in older persons. Neuroepidemiology. 2008;31(3):174-80.
• 12. Garcia PA, Dias JM, Dias RC, Santos P, Zampa CC. A study on the relationship between muscle function, functional mobility and level of physical activity in community-dwelling elderly. Rev Bras Fisioter. 2011;15(1):15-22.
• 12. Siafakas NM, Stathopoulou M, Tzanakis N, Mitrouska I, Tsoumakidou M, Georgopoulos D. Effect of digoxin on global respiratory muscle strength after cholecystectomy: a double blind study. Thorax. 2000;55(6):497-501.
• 13. Sánchez-García S, García-Peña C, Duque-López MX, Juárez-Cedillo T, Cortés-Núñez AR, Reyes-Beaman S. Anthropometric measures and nutritional status in a healthy elderly population. BMC Public Health. 2007;7:2.
• 14. Figueiredo IM, Sampaio RF, Mancini MC, Silva FCM, Souza MAP. Teste de força de preensão utilizando o dinamômetro Jamar. Acta Fisiatr. 2007;14(2):104-10.
• 15. Batistoni SS, Neri AL, Cupertino AP. Validity of the Center for Epidemiological Studies Depression Scale among Brazilian elderly. Rev. Saude Publica. 2007;41(4):598-605.
• 17. Shinkai S, Watanabe S, Kumagai S, Fujiwara Y, Amano H, Yoshida H, et al. Walking speed as a good predictor for the onset of functional dependence in a Japanese rural community population. Age Ageing. 2000;29(5):441-6.
• 18. Lustosa LP, Pereira DS, Dias RC, Britto RR, Parentoni AN, Pereira LSM. Tradução e adaptação transcultural do Minnesota Leisure Time Activities Questionnaire em idosos. Geriatria & Gerontologia. 2011;5:57-65.
• 19. Souza RB. Pressões respiratórias estáticas máximas. J Pneumol. 2002;28:155-165.
• 20. Miranda AS, Novaes RD, Ferreira AE, Neves MP, Corrêa CL, Mendonça VA. Assessment of respiratory muscle strength, peak expiratory flow and pain after open cholecystectomy. Acta Gastroenterol Latinoam. 2009;39(1):38-46.
• 21. Jekel JF, Katz DL, Wild D, Elmore JG. In: Epidemiology, biostatistics and preventive medicine. 2ed. Philadelphia: Elsevier; 2001.
• 22. Simões RP, Castello V, Auad MA, Dionísio J, Mazzonetto M. Prevalence of reduced respiratory muscle strength in institutionalized elderly people. Sao Paulo Med J. 2009;127(2):78-83.
• 23. Geraldes AAR, Oliveira ARM, Albuquerque RB, Carvalho JM, Farinatti PTV. A Força de preensão manual é boa preditora do desempenho funcional de idosos frágeis: um estudo correlacional múltiplo. Rev Bras Med Esporte. 2008;14(1):12-6.
• 24. Neto LSS, Karnikowiski MGO, Tavares AB, Lima RM. Associação entre sarcopenia, obesidade sarcopênica e força muscular com variáveis relacionadas de qualidade de vida em idosas. Rev Bras Fisioter. 2012;16(5):360-7.
• 25. Buchman AS, Boyle PA, Wilson RS, Gu L, Bienias JL, Bennett DA. Pulmonary function, muscle strength and mortality in old age. Mech Ageing Dev. 2008;129(11):625-31.
• 26. Taekema DG, Gussekloo J, Maier AB, Westendorp RG, de Craen AJ. Handgrip strength as a predictor of functional, psychological and social health. A prospective population-based study among the oldest old. Age Ageing 2010;39(3);331-7.
• 27. Macedo C, Gazzola JM, Najas M. Síndrome da fragilidade no idoso: importância da fisioterapia. Arq Bras Ciênc Saúde. 2008;33(3):177-84.
• 28. Liu CK, Fielding RA. Exercise as an intervention for frailty. Clin Geriatr Med. 2011;27(1):101-10.
• 29. Weiss CO, Hoenig HH, Varadhan R, Simonsick EM, Fried LP. Relationships of cardiac, pulmonary, and muscle reserves and frailty to exercise capacity in older women. J Gerontol A Biol Sci Med Sci. 2010;65(3):287-94.
• 30. Watsford M, Murphy A. The effects of respiratory-muscle training on exercise in older women. J Aging Phys Act. 2008;16(3):245-60.
• 31. Syddall H, Cooper C, Martin F, Briggs R, Sayer A. Is grip strength a useful single marker of frailty? Age Ageing. 2003;32(6):650-6.

Comparison of respiratory muscle strength between fragility subgroups in community elderly

Comparación de la fuerza muscular respiratoria entre los subgrupos de fragilidad en añosas de la comunidad

Publication Dates

• Publication in this collection
  23 Jan 2014
• Date of issue
  Dec 2013

History

• Received
  Apr 2013
• Accepted
  Nov 2013