Activity of daily living improvement after cataract surgery for patients in nursing care facilities

ABSTRACT

BACKGROUND

Whether the improvement in activities of daily living (ADL) after cataract surgery in patients from nursing care facilities is comparable with that in patients from home remains unclear.

METHODS

Data of patients who underwent cataract surgery from April 2014 to March 2015 were extracted from a national inpatient database in Japan. We identified 222,883 patients hospitalized from home and 1,228 patients hospitalized from nursing care facilities who underwent cataract surgery during hospitalization. A retrospective matched-pair cohort study was performed to compare the proportion of patients with improved ADL after cataract surgery. The primary outcome was the proportion of patients with improved ADL after cataract surgery. ADL assessment was performed by calculating the Barthel index. We also compared the length of hospital stay between the groups.

RESULTS

Patients from nursing care facilities were more likely to be older and female and to have a higher comorbidity index and lower ADL score at admission. In the matched-pair analysis of 1,228 vs. 24,560 pairs, a lower proportion of patients hospitalized from nursing care facilities had an improved ADL score (odds ratio, 0.64; 95% confidence interval, 0.53–0.78; p < 0.001). There was no significant difference in the length of hospital stay between the groups.

CONCLUSIONS

In this large nationwide cohort of patients with cataracts, hospitalization from nursing homes was significantly correlated with poor improvement in ADL compared with hospitalization from home. These results suggest that early cataract surgery prior to admission to nursing care facilities should be recommended for patients with cataracts.

INTRODUCTION

Cataract surgery is the most frequently performed surgical procedure in people aged ≥65 years in the Western world [1]. Major advancements in surgical and intraocular lens technology have led to tremendous increases in surgical volume because of the improved safety profile and visual outcomes.

In Japan, almost 25% of people aged >75 years currently need nursing care [2]. In the United States, the number of people using nursing facilities, alternative residential care places, or home care services is projected to increase from 15 million in 2000 to 27 million in 2050 [3]. The need for cataract surgery among patients in nursing care facilities is therefore increasing and becoming an important public health issue.

Although studies have provided clear evidence that cataract surgery improves vision and quality of life among community-dwelling adults [4, 5], only a few studies have assessed patients’ activities of daily living (ADL) after cataract surgery in patients from nursing care facilities [6–8]. Because these previous studies involved only small numbers of patients from a single institution or small numbers of institutions with different outcome measures, it remains unclear whether the effectiveness of cataract surgery in patients from nursing care facilities is comparable with that in patients from home in terms of improvement in ADL.

The aim of the present study was to investigate the effect of cataract surgery in patients from nursing care facilities using a large nationwide inpatient database in Japan.

METHODS

STUDY DESIGN AND SETTING

In the present retrospective matched-pair cohort study, we used the Diagnosis Procedure Combination database, which is a Japanese national administrative claims and discharge abstract database. The details of the database and its data have been described elsewhere [9–11]. The database includes administrative claims data and some detailed clinical data for about 7 million inpatients per year in approximately 1,000 participating hospitals. The database includes the following information: patient age and sex; main diagnoses; surgical procedures; comorbidities that were already present at admission and complications that occurred after admission, recorded using International Classification of Diseases, 10th Revision codes; and length of stay. The database has information on the following 10 components of the Barthel index (BI) [12] for each patient: feeding, bathing, grooming, dressing, bowels, bladder, toilet use, transfer, morbidity, and stairs. Scores of 0 to 3 points are recorded for each component in accordance with the BI scoring system. The BI is a measure of physical dependence in personal ADL and is one of the most frequently employed questionnaires for the evaluation of personal functionality. The score derived from the questionnaire is considered to be a quantitative measure of ADL, in which 100 is the best score and 0 is the worst score (100: independent; ≤85: need a small amount of assistance; ≤60: need assistance mainly with ADL; ≤40: need a large amount of assistance, and assistance is required for almost all items; ≤20: total assistance required). The individual points of the 10 components are summed up to calculate the BI score. The attending physicians are responsible for patient data entry regarding diagnoses and outcomes including the BI score at discharge. In addition, information on housing before hospitalization, such as home and nursing care facilities, is also recorded. This study was approved by the Institutional Review Board of The University of Tokyo. The requirement for informed consent was waived owing to the anonymous nature of the data.

PATIENT SELECTION AND STUDY SETTING

Among patients hospitalized from 1 April 2014 to 31 March 2015, we selected those who underwent one-eye cataract surgery during hospitalization. Among 227,789 patients who satisfied the inclusion criteria, we excluded the following: 3,648 patients who received simultaneous vitrectomy, 36 patients who underwent simultaneous glaucoma surgery, and 4 patients who received simultaneous keratoplasty. After considering the duplicate cases, 3,678 patients were excluded. The remaining 224,111 patients were categorized into two groups based on their residence: those hospitalized from nursing care facilities and those hospitalized from home.

VARIABLES AND OUTCOMES

We obtained data on the following baseline variables: age, sex, and comorbidities present at admission. Comorbidities were scored according to the updated Charlson comorbidity index (CCI) [13]. The CCI, a method of predicting mortality by classifying or weighting comorbidities such as cancer, liver disease, AIDS/HIV, and others, has been widely used by health researchers to measure the burden of disease and case mix. The score is considered to be a quantitative measure of the comorbidity burden, in which 0 is the best score and 24 is the worst score. The primary outcome was improvement in the ADL score after cataract surgery. Patients with an improved ADL score were defined as those who had a higher BI score at discharge than at admission. The secondary outcome was the length of hospital stay.

STATISTICAL ANALYSES

We used a matched-pair cohort design to select the case group (patients hospitalized from nursing care facilities) and the control group (patients hospitalized from home) by means of 1:20 matching. For each patient in the case group, we identified a set of control patients who had the same BI score at admission. We then randomly selected 20 controls per individual in the case group from the pooled population of controls.

Differences in demographic and clinical characteristics between the groups were compared in unmatched and matched populations using Fisher’s exact probability tests for categorical variables or a t-test for continuous variables. Demographic variables included age, sex, CCI, and BI score at admission. In the matched population, the proportions of patients with an improved ADL score after cataract surgery and the length of hospital stay were compared between the nursing care facilities and home groups using Fisher’s exact probability test or a t-test. The proportion of patients with an improved ADL score after cataract surgery was compared between the matched pairs using a multivariable conditional logistic regression model. The length of hospital stay was compared between the matched pairs using multiple linear regression. To account for clustering of matched pairs, the linear regression model was fitted with generalized estimating equations [14]. All demographic and clinical variables used in the univariate analysis were entered into the multiple regression analyses. We set the level of statistical significance at p < 0.05 (two-sided). All statistical analyses were performed using Stata version 15 (StataCorp, College Station, TX).

RESULTS

We identified 224,111 patients who underwent one-eye cataract surgery during hospitalization. Their mean age was 74.1 years (standard deviation, 9.7 years), and 42.6% of patients were men. Of the entire cohort, the number of patients in the nursing care facility group and the home group was 1,228 (0.5%) and 222,883 (99.5%), respectively. Pairwise matching created a final study cohort of 1,228 patients hospitalized from nursing care facilities and 24,560 controls hospitalized from home.

Table 1 shows the demographic and clinical characteristics of the unmatched and matched populations. Compared with the patients in the home group, those in the nursing care facility group were more likely to be older and female and to have a higher CCI. Before matching, the BI at admission in the nursing care facility group was much lower than that in the home group (68.6 vs 97.8, respectively; p < 0.001). After pair matching, the BI at admission was closely balanced between the two groups.

Table 1 Demographic and baseline clinical characteristics of patients undergoing cataract surgery hospitalized from home or nursing care facilities in the unmatched and matched-pair populations

	Unmatched group			Matched group
	Homes	Nursing care facilities	p value	Homes	Nursing care facilities	p value
No. of patients	222,883	1,228		24,560	1,228
Age, years (SD)	74.1 (9.7)	81.2 (9.5)	<0.001	77.4 (10.0)	81.2 (9.5)	<0.001
Male sex (%)	95,157 (43)	387 (32)	<0.001	11,176 (46)	387 (32)	<0.001
CCI score (SD)	0.1 (0.4)	0.3 (0.8)	<0.001	0.2 (0.5)	0.3 (0.8)	<0.001
BI score (SD) at admission	97.8 (9.8)	68.6 (31.5)	<0.001	68.6 (31.4)	68.6 (31.5)	1.00

SD: standard deviation, CCI: Charlson comorbidity index, BI: Barthel index.

Table 2 shows the unadjusted comparisons of the proportion of patients with an improved ADL score after cataract surgery and the length of hospital stay between the two groups in the populations matched according to BI at admission. The crude proportion of patients with an improved ADL score after cataract surgery was significantly lower in patients hospitalized from nursing care facilities than from home (89.6% vs. 93.7%, respectively; p < 0.001). There was no significant difference in the length of hospital stay between the groups.

Table 2 Unadjusted comparisons of postoperative outcomes following cataract surgery between patients hospitalized from home and nursing care facilities

	Home (N = 24,560)	Nursing care facilities (N = 1,228)	p value
Proportion of patients with ADL improvement (%)	93.7	89.6	<0.001
Length of hospital stay, d, mean (SD)	3.2 (2.2)	3.2 (3.2)	0.36

ADL: activities of daily living, SD: standard deviation.

Table 3 shows the results of the multivariable conditional logistic regression analysis for improved ADL scores after cataract surgery. Compared with the patients hospitalized from home, those from nursing care facilities had a significantly lower proportion of an improved ADL score even after adjusting for other variables (odds ratio, 0.64; 95% confidence interval, 0.53–0.78; p < 0.001). Again, there was no significant difference in the length of hospital stay between the two groups.

Table 3 Multivariable logistic regression analysis for ADL improvement and multiple linear regression analysis for length of hospital stay between patients from home and nursing care facilities

	Odds ratio*	95% Confidence interval	p value
ADL improvement
Patients hospitalized from home	reference
Patients hospitalized from nursing care facilities	0.64	0.53–0.78	<0.001
	Coefficient*	95% Confidence interval	p value
Length of hospital stay, days
Patients hospitalized from home	reference
Patients hospitalized from nursing care facilities	0.13	−0.06–0.31	0.18

* adjusted for age, sex, and Charlson comorbidity index score

ADL: activities of daily living.

DISCUSSION

Using a large nationwide database in Japan, the present study compared ADL after cataract surgery between patients hospitalized from nursing care facilities and patients hospitalized from home, with adjustment for the patients’ characteristics. The results of this study demonstrated a substantial difference in the patients’ characteristics between the nursing care facility group and the home group. We therefore conducted a matched-pair cohort analysis to adjust for measured variables. The results revealed that the proportion of patients with an improved ADL score after cataract surgery between admission and discharge was significantly lower in the nursing care facility group than in the home group. In contrast, there was no significant difference in the length of hospital stay.

Few studies have focused on cataract surgery in nursing home residents. One prospective cohort study (surgery group, n = 19 vs. no-surgery group, n = 22) showed that compared with the no-surgery group, the cataract surgery group exhibited significantly improved scores for visual acuity [6]. In another prospective cohort study (surgery group, n = 30 vs. no-surgery group, n = 15), residents in the cataract surgery group reported improved general vision, fewer limitations imposed by their vision, less difficulty in reading, less anxiety, less frustration and/or emotional upset over their vision, and greater ease and likelihood of engaging in social interactions [7]. In contrast, another prospective cohort study (surgery group, n = 30 vs. no-surgery group, n = 15) showed that participants undergoing cataract surgery did not experience significant functional changes compared with either their baseline scores or the no-surgery control group [8]. Previous studies have confirmed the benefits of cataract surgery to improve vision and quality of life among community-dwelling adults [4, 5], and these benefits were extrapolated to nursing home residents despite these studies including small numbers of patients from a single nursing home or small numbers of nursing homes. To the best of our knowledge, however, no study has compared the outcome of cataract surgery for nursing care facility residents versus home residents. Nursing care facility residents are generally more likely to have limitations in physical ability than are community-dwelling older people [15]; therefore, we adjusted for the ADL score at admission with matching and examined the difference in the outcomes between the two groups. We found that the effectiveness of cataract surgery in patients from nursing care facilities was inferior to that in patients from home.

Much of the vision impairment in patients from nursing care facilities is due to correctable conditions such as refractive error and cataract [16], and studies of nursing home residents have documented high rates of vision-impairing cataract [17]. The uptake of cataract surgery is poor in nursing care facilities because of barriers such as the difficulty of testing vision, the difficulty of transportation, and the lack of patient advocates to help in scheduling appointments [18]. The lack of willingness of family members, guardians, and the residents themselves to consent to surgery is another important barrier [18]. Complications of surgery are likely to occur when cataracts are in their advanced stage, such as brunescent, white, dense, and total cataracts [19]. Various factors such as difficulty in keeping patients still during surgery under local anesthesia and the inability to maintain rest after surgery may also explain the worse outcomes of cataract surgery in patients from nursing care facilities. Cataract surgery is reportedly related to improvement in dementia and depression as well as prevention of falls [20, 21]. Moreover, the cost-effectiveness is very high [22]. Taken together with our findings, these data indicate that performance of cataract surgery in an earlier stage of life, before the patient enters a nursing care facility, may be preferable.

The primary strength of this study is that we compared the outcome of cataract surgery between nursing care facility residents and home residents. We used a national inpatient database of many patients to collect demographic and clinical variables of more than 1,200 individuals residing in nursing care facilities. To the best of our knowledge, the only publications on the effectiveness of cataract surgery in nursing care facility residents are three cohort studies with no controls and small sample sizes. Thus, our findings may be more generalizable to patients with cataract in nursing care facilities. By utilizing a large database, we were able to conduct our analyses with the data of many individuals. Additionally, we performed a matched-pair cohort analysis with baseline ADL characteristics. The patients in the nursing care facility group were more likely to have lower ADL at admission than the patients in the home group. This tendency may have caused bias by the presence of a confounding characteristic between patients’ residences and outcomes. However, we successfully adjusted for such confounding variables by using matched-pair cohort analyses between nursing care facilities and home groups.

Our study had several limitations. First, instead of using visual acuity and vision-related quality of life as outcomes, we used ADL (the BI). We used ADL because the database did not contain results of vision testing or records of medical charts, and the BI score has a ceiling effect [23] that would make outcomes less sensitive to the benefits of an intervention. A previous study showed a significant association between visual acuity and the BI score in patients with cataract [24], and the ADL improvement is an important outcome of cataract surgery, as are improvement in visual acuity and the visual field. Second, the timing of the outcome measurement in this study was too early. The final evaluation of cataract surgery is usually performed after a few months [5–8]; however, we evaluated outcomes at discharge, which was several days after surgery in most cases. Early evaluation may also be a source of underestimation. In conventional small-incision cataract surgery, visual acuity is greatly improved several days after surgery [25, 26]. Notably, however, we were able to detect the differences in the outcomes between the two groups even after a short time after surgery. Third, because we excluded patients who had undergone simultaneous surgeries such as vitrectomy and glaucoma surgery, we could not examine other ocular conditions that may have been comorbid with cataracts. Fourth, although measured confounders were adjusted by the matched-pair cohort and multivariable analyses, the results could still be biased by unmeasured confounders such as the stage of cataract, ocular complications, and history of other eye diseases. Finally, our results may not be generalizable to patients who undergo cataract surgeries in an outpatient department setting. In general, patients with cataract complicated by many systemic diseases often undergo operations on admission rather than outpatient surgery. Nursing home residents are more likely than community-dwelling older people to have visual impairments [7], cognitive impairments [27], and physical function limitations [15]. Therefore, cataract surgery for nursing home residents is often performed at hospital admission. Moreover, according to the national database of health insurance claims and open data on specific health checkups in Japan [28], the proportions of women and older people are higher among hospitalized patients than outpatients undergoing cataract surgery (female:male ratio: 1.43 vs. 1.27, respectively and proportion of patients aged ≥75 years: 55% vs. 47%, respectively). Because the proportions of women and older people were high in our research sample (Table 1), the results of present study seem to reflect the current situation of cataract surgery.

CONCLUSIONS

ADL improvement after cataract surgery in patients from nursing care facilities was significantly lower than that in patients from home. Earlier cataract surgery performed before the patient enters a nursing care facility should be recommended.

ACKNOWLEDGMENTS

This work was supported by grants from the Ministry of Health, Labour and Welfare, Japan (H30-Policy-Designated-004 and H29-ICT-General-004); Ministry of Education, Culture, Sports, Science and Technology, Japan (17H04141); and Japan Agency for Medical Research and Development (19dk0310083h0003).

CONFLICTS OF INTEREST

There are no conflicts of interest to declare.

REFERENCES

• 1.   Ellwein  LB,  Urato  CJ. Use of eye care and associated charges among the Medicare population: 1991–1998. Arch Ophthalmol 2002;120:804–811.
• 2.  Cabinet office, government of Japan. Annual Report on the Aging Society: 2017. http://www8.cao.go.jp/kourei/whitepaper/w-2017/html/zenbun/index.html. Accessed 2018 December 28.
• 3.   Harris-Kojetin  L,  Sengupta  M,  Park-Lee  E,  Valverde  R. Long-Term Care Services in the United States: 2013 Overview. Vital Health Stat 3 2013;37:1–107.
• 4.   Javitt  JC,  Brenner  MH,  Curbow  B,  Legro  MW,  Street  DA. Outcomes of cataract surgery. Improvement in visual acuity and subjective visual function after surgery in the first, second, and both eyes. Arch Ophthalmol 1993;111:686–691.
• 5.   Steinberg  EP,  Tielsch  JM,  Schein  OD,  Javitt  JC,  Sharkey  P,  Cassard  SD, et al. National study of cataract surgery outcomes. Variation in 4-month postoperative outcomes as reflected in multiple outcome measures. Ophthalmology 1994;101:1131–1140.
• 6.   Marx  MS,  Werner  P,  Billig  N,  Watson  VJ,  Cohen-Mansfield  J,  Feldman  R. Outcomes of Cataract Surgery in Nursing Home Residents. Psychosomatics 1995;36:254–261.
• 7.   Owsley  C,  McGwin  G,  Scilley  K,  Meek  GC,  Seker  D,  Dyer  A. Impact of cataract surgery on health-related quality of life in nursing home residents. Br J Ophthalmol 2007;91:1359–1363.
• 8.   Elliott  AF,  McGwin G  Jr,  Owsley  C. Vision-enhancing interventions in nursing home residents and their short-term effect on physical and cognitive function. J Am Geriatr Soc 2009;57:202–208.
• 9.   Matsuda  S,  Fujimori  K,  Kawabata  K,  Ishikawa  KB,  Fushimi  K. Diagnosis procedure combination as an infrastructure for the clinical study. Asia Pacific Journal of Disease Management 2011;5:81–87.
• 10.   Yasunaga  H,  Horiguchi  H,  Kuwabara  K,  Matsuda  S,  Fushimi  K,  Hashimoto  H, et al. Outcomes after laparoscopic or open distal gastrectomy for early-stage gastric cancer: a propensity-matched analysis. Ann Surg 2013;257:640–646.
• 11.   Isogai  T,  Yasunaga  H,  Matsui  H,  Tanaka  H,  Ueda  T,  Horiguchi  H, et al. Out-of-hospital versus in-hospital Takotsubo cardiomyopathy: analysis of 3719 patients in the Diagnosis Procedure Combination database in Japan. Int J Cardiol 2014;176:413–417.
• 12.   Mahoney  FI,  Barthel  DW. Functional evaluation: the barthel index. Md State Med J 1965;14:61–65.
• 13.   Quan  H,  Li  B,  Couris  CM,  Graham  P,  Hider  P, et al. Updating and validating the Charlson comorbidity index and score for risk adjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol 2011;173:676–682.
• 14.   Hanley  JA,  Negassa  A,  Edwardes  MD,  Forrester  JE. Statistical Analysis of Correlated Data Using Generalized Estimating Equations: An Orientation. Am J Epidemiology 2003;157:364–375.
• 15.   Falconer  M,  O’Neill  D. Profiling disability within nursing homes: a census-based approach. Age Ageing 2007;36:209–213.
• 16.   Owsley  C,  McGwin  G,  Scilley  K,  Meek  GC,  Dyer  A,  Seker  D. The visual status of older persons residing in nursing homes. Arch Ophthalmol 2007;125:925–930.
• 17.   Tielsch  JM,  Javitt  JC,  Coleman  A,  Katz  J,  Sommer  A. The prevalence of blindness and visual impairment among nursing home residents in Baltimore. N Engl J Med 1995;332:1205–1209.
• 18.   Friedman  DS,  Muñoz  B,  Roche  KB,  Massof  R,  Broman  A,  West  SK. Poor uptake of cataract surgery in nursing home residents. The Salisbury Eye Evaluation in nursing home groups study. Arch Ophthamol 2005;123:1581–1587.
• 19.   Kim  BZ,  Patel  DV,  McKelvie  J,  Sherwin  T,  McGhee  CNJ. The Auckland Cataract Study II: Reducing Complications by Preoperative Risk Stratification and Case Allocation in a Teaching Hospital. Am J Ophthalmol 2017;181:20–5.
• 20.   Ishii  K,  Kabata  T,  Oshika  T. The impact of cataract surgery on cognitive impairment and depressive mental status in elderly patients. Am J Ophthalmol 2008;146:404–409.
• 21.   Harwood  RH,  Foss  AJ,  Osborn  F,  Gregson  RM,  Zaman  A,  Masud  T. Falls and health status in elderly women following first eye cataract surgery: a randomized controlled trial. Br J Ophthalmol 2005;89:53–59.
• 22.   Hiratsuka  Y,  Yamada  M,  Akune  Y,  Murakami  A,  Okada  AA,  Yamashita  H, et al. Eye Care Comparative Effectiveness Research Team (ECCERT) Cost-utility analysis of cataract surgery in Japan: a probabilistic Markov modeling study. Jpn J Ophthalmol 2013;57:391–401.
• 23.   Sarker  SJ,  Rudd  AG,  Douiri  A,  Wolfe  CD. Comparison of 2 extended activities of daily living scales with the Barthel Index and predictors of their outcomes: cohort study within the South London Stroke Register (SLSR). Stroke 2012;43:1362–1369.
• 24.   Datta  S,  Foss  AJ,  Grainge  MJ,  Gregson  RM,  Zaman  A,  Masud  T, et al. The importance of acuity, stereopsis, and contrast sensitivity for health-related quality of life in elderly women with cataracts. Invest Ophthalmol Vis Sci 2008;49:1–6.
• 25.   van Zyl  L1,  Kahawita  S,  Goggin  M. Manual small incision extracapsular cataract surgery in Australia. Clin Exp Ophthalmol 2014;42:729–733.
• 26.   Krarup  T,  Holm  LM,  la Cour  M,  Kjaerbo  H. Endothelial cell loss and refractive predictability in femtosecond laser-assisted cataract surgery compared with conventional cataract surgery. Acta Ophthalmol 2014;92:617–622.
• 27.  Prince M, Prina M, Guerchet M. World Alzheimer Report 2013: Journey of Caring-Analysis of Long-Term Care for Dementia. London: Alzheimer’s Disease International, 2015.
• 28.  Ministry of Health, Labour and Welfare. The 3^rd NDB open data Japan. https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000177221_00002.html. Accessed 2019 Jun 27.