An expected 3.4 million women aged 60 years or older will be affected by pelvic organ prolapse (POP) by 2050.1,2 Older women are increasingly undergoing POP surgery and are at increased risk for worse postoperative outcomes than younger women as a result of physiologic vulnerability.3,4 Sung et al4 reported that older women undergoing POP surgery are at increased risk for cardiopulmonary complications. Factors that identify women at increased risk for worse outcomes are not known.
Functional status is the ability to perform activities essential to independent living such as walking and lifting 10 pounds. Studies from other surgical specialties suggest that even in the absence of postoperative complications, older adults can have worsening of postoperative functional status resulting in disability, long-term care needs, and dependency at home.3,5–7 Objective markers of functional status were useful predictors of worse functional outcomes after cardiac and abdominal surgery in older mostly male patients.3,8 Data on the postoperative functional status of older women undergoing POP surgery are limited.9,10 It remains unclear whether older women undergoing POP surgery are at increased risk for worse postoperative functional outcomes and whether such outcomes can be predicted by preoperative risk factors.
Our aim is to evaluate whether preoperative markers of functional status can predict postoperative functional outcomes after undergoing POP surgery. Our a priori hypothesis was that women with worse preoperative functional status would have greater functional limitations, slower return to baseline functional status, and longer length of stay after prolapse surgery.
MATERIALS AND METHODS
We performed a longitudinal prospective cohort study of older women undergoing surgery for POP between November 2011 and June 2013. Approval was obtained from the University of Pennsylvania institutional review board. Our inclusion criteria were English-speaking women, age 60 years or older, planning surgery for POP stage 2 or higher. We recruited women at their preoperative appointment.
After obtaining informed consent, baseline functional status was assessed preoperatively using the following functional status assessment tools: 1) Activities of Daily Living,11,12 2) Instrumental Activities of Daily Living Scale,13 and 3) number of functional limitations using a questionnaire used in the Health and Retirement Study14,15 (Appendices 1 and 2). Functional limitations measured included difficulty in walking several city blocks, walking 1 city block, walking across a room, sitting for approximately 2 hours, getting up from a chair after sitting for long periods, picking up a dime from a table, extending one's arms above shoulder level, pushing or pulling large objects like a living room chair, climbing several flights of stairs, climbing one flight of stairs, lifting 10 pounds, or kneeling, stooping, or crouching down. Disability was considered to be present if women required assistance or could not perform one or more of either the Activities of Daily Living or the Instrumental Activities of Daily Living. The response for each functional limitation was recorded as “no difficulty,” “a little difficulty,” “some difficulty,” or not applicable. A functional limitation was defined as being present if the response was “a little” or “more difficulty” for each limitation. The number of potential limitations ranged from 0–12.
Frailty has also been shown to be related to postoperative functional status and surgical morbidity and multiple markers of frailty have been described.8,16 In this study, women were identified as frail if one of the following markers were present: 1) impaired cognition defined as score less than 3 on the Mini-Cog Assessment Instrument,17 2) history of weight loss of 10 or more pounds in past 6 months,16 3) one or more falls in the past 6 months,18 4) depression (defined as score of more than than 1 on the five-item Geriatric Depression Scale score),16,19–21 and 5) anemia defined as hematocrit less than 35%.3 The Mini-Cog Assessment is a three-word recall for short-term memory and drawing a clock face with a specified time. The Mini-Cog was administered by a research assistant. The five-item Geriatric Depression Scale has been validated in multiple settings and populations of elderly patients16,19–21 and has the benefit of being self-administered.
The number of comorbidities was assessed using the Functional Co-morbidity Index, which assesses comorbidities such as diabetes, myocardial infarction, hearing loss, and depression and can range in score from 0 to 18.22 The Functional Co-morbidity Index is a better predictor of quality of life as measured by the SF-36 than other indices.22 Demographic data, preoperative hematocrit, POP-quantification stage,23 and American Society of Anesthesiologists class were obtained from the patient's chart. American Society of Anesthesiologists class has been previously reported as a useful marker of functional status in orthopedic patients24 and in women with POP.10
Surgery for POP was performed by one of three fellowship-trained pelvic reconstructive surgeons in the University of Pennsylvania Health System. Data on the type of surgical procedure for prolapse (open, robotic-assisted, vaginal reconstructive, or obliterative), coincidental anti-incontinence surgery, and complications were collected from the operative record.
Postoperative data were collected through a combination of structured questionnaires and medical record review. Functional status using the described assessment tools was measured at 6 weeks (range 4–8 weeks) and 12 weeks (range 10–14 weeks) after surgery. Data regarding hospital readmissions and admission to a skilled nursing facility and postoperative complications were collected by reviewing the inpatient and outpatient medical records and structured questionnaires administered to patients at their postoperative visits or by telephone call.
Complications were graded retrospectively using the modified Dindo Harm Scale.25 For patients who had more than one complication, the most severe complication was used to determine the grade. The modified Dindo Harm Scale is based on the type of therapy needed to correct the complication.25 In brief, using this system, grade 1 is any deviation from the normal postoperative course without the need for pharmacologic, surgical, endoscopic, or radiologic interventions; a grade 2 complication requires pharmacologic treatments; a grade 3 complication requires invasive interventions such as return to the operating room, whereas a grade 4 complication requires more invasive interventions such as critical care support. The data abstractor grading the complication was blinded to preoperative markers of functional status, frailty, and comorbidity.
Analyses were performed using STATA 12.0. Demographic variables and preoperative functional status markers (number of functional limitations, history of recent weight loss, and American Society of Anesthesiologists class) were summarized using mean or median for continuous variables and proportions for categorical variables. We used the Friedman test to compare the median number of functional limitations over time (from baseline to 6 and 12 weeks).
We had several outcomes for this study. The primary outcome was the number of postoperative functional limitations. Our secondary outcomes were failure to return to baseline functional status (yes or no) and length of stay. Failure to return to baseline functional status was defined as the presence of two or more additional functional limitations at 12 weeks after surgery because we considered this to be more clinically meaningful in an overall healthy surgical population.5,6 Length of stay in a medical facility was defined as total number of days in a medical facility including initial hospital length of stay and any additional stays in a skilled nursing facility or during hospital readmission for any cause during the first 12 weeks after surgery.
We determined the association of preoperative functional status markers with postoperative outcomes (functional limitations and length of stay) using univariable and multivariable regression. Coefficients for the number of postoperative functional limitations and number of days length of stay were determined rather than relative risks. We compared continuous preoperative variables between women who did or did not return to baseline functional status using the Wilcoxon rank-sum test and categorical variables using the χ2 test. Risk ratios for failure to return to baseline functional status using univariable and multivariable logistic regression were determined. A variable was retained in the final multivariable model if it was associated with postoperative functional limitations with P<.2.26
Based on data from the general surgery literature,5 the baseline functional score in older adults undergoing abdominal surgery was 12.7±8.2. In that study, the mean functional status score at 12 weeks postoperatively was 16. At 80% power and a two-tailed α of 0.05, a sample size of 126 women was required to detect a change of two or more limitations. We planned to recruit 132 women, allowing for 5% loss-to-follow-up.
Of the 137 eligible women during the study period, 132 women agreed to participate in the study. Five women withdrew either as a result of surgical cancellation or patient request, resulting in 127 participants (Fig. 1). Functional status data were available in 111 of 127 women at 6 weeks and in 110 of 127 women at 12 weeks resulting in a missing data rate of 13.4% (17/127). For these 17 women, the reason for missing data was our inability to administer the functional status instruments within the appropriate window of the 12-week visit (±2 weeks). All patients with missing data had follow-up visits with the surgeon within 6 months postoperatively, allowing us to collect data on complications and length of stay on these patients. Women with missing data were significantly older (72.2±5.7 years) than women for whom complete data were available (68.6±7.2 years, P=.04); however, there were no significant differences in length of stay (3.3±1.4 compared with 2.9±0.7 days) and severity of postoperative Dindo grade complications (grade 1: 17.7% compared with 11.9%; grade 2: 29.4% compared with 21.1%; grade 3: 5.9% compared with 3.7%, P=.64) between women with and without missing data.
The mean age of the cohort of 127 women was 69.1±7.1 years, and white women comprised 80.6% of the cohort. The median (range) parity was three (range 0–10) and 83.5% had stage 3 POP. Median Functional Co-morbidity Index score was 3 (range 0–7). Mean body mass index (calculated as weight (kg)/[height (m)]2) was 27.7±4.4, and mean preoperative hematocrit was 39.1±3.6%. The prevalence of frailty markers in the cohort was as follows: impaired cognition 15.8% (20/127), history of 10 or more pounds of weight loss in the past 6 months 15.8% (20/127), falls in the past 6 months 14.2% (18/127), anemia 11.8% (15/127), and depression 7.9% (10/127). At least one frailty marker was present in 57 of 127 (45%) women.
The American Society of Anesthesiologists class distributions were as follows: class I 1.6% (2/127), class II 76.3% (94/127), class III 22.0% (27/127), and class IV or higher 0%. The type of surgical procedures performed included 45.7% (58/127) vaginal reconstructive surgery, 36.2% (46/127) robotic-assisted surgery, 14.2% (18/127) open abdominal surgery, and 3.9% (5/127) underwent obliterative surgery. Median (range) preoperative functional limitations for women undergoing each of these prolapse surgeries were 3.5 (0–9), three (0–10), two (0–10), and five (0–10), respectively (P=.43, χ2). Of the 127 women, 62 (48.8%) had a concomitant anti-incontinence procedure. During the study, the rate of complications was as follows: Dindo grade 1, 12.7% (16/127); Dindo grade 2, 22.2% (28/127); and Dindo grade 3, 4.0% (5/127).
The median (range) of preoperative functional limitations at baseline in the cohort was three (0–10). Of the potential 12 limitations assessed (Appendix 2), half (50%) of the women reported difficulty stooping, kneeling, or crouching down, whereas 25% women reported difficulty walking several blocks, getting up from a chair after sitting for a long period of time, climbing several flights of stairs without resting, lifting or carrying a heavy bag of groceries, and pushing or pulling a living room chair. Less than 10% women reported difficulty in other limitations (walking 1 block, walking across a room, sitting for 2 hours, climbing one flight of stairs without resting, picking up a dime from the table, and reaching or extending arms above shoulder level). Only 11 of 127 women (8.7%) reported preoperative disability in one or more Instrumental Activities of Daily Living; no disabilities in the Activities of Daily Living were reported (Appendix 1).
Table 1 shows the change in the median number of functional limitations over time. At baseline, the median number of limitations in women in American Society of Anesthesiologists class III was lower than the median number of limitations in American Society of Anesthesiologists class I–II; however, 39% (11/28) women in class III had five or more limitations as compared with only 27% (27/99) in class I–II. There was no change in the median number of functional limitations from baseline to 6 and 12 weeks postoperatively for women in American Society of Anesthesiologists class I–II. For women in American Society of Anesthesiologists class III and the cohort as a whole, the median number of functional limitations significantly increased from baseline to 6 weeks and then declined to baseline levels at 12 weeks (Table 1).
On univariable linear regression, factors significantly associated with the number of postoperative functional limitations were age (P<.03), the number of preoperative functional limitations (P<.001), Functional Co-morbidity Index (P<.001), and depression (P<.002). On multivariable linear regression, after controlling for age, number of preoperative functional limitations, Functional Co-morbidity Index, depression, surgeon, type of procedure, and complication severity, the presence of a preoperative functional limitation predicted an increase of 0.55 functional limitations (95% confidence interval [CI] 0.36–0.74; P<.001) after surgery.
For the 110 women for whom 12-week postoperative functional status data were available, 78 (70.9%) women reported the same, less, or one more functional limitation than their preoperative limitations and were classified as having returned to baseline functional status. At the 12-week visit, 32 (29.1%) women reported two or more additional functional limitations and were classified as not returning to baseline functional status. Women who did not return to baseline functional status were significantly more likely to report history of recent weight loss of more than 10 pounds (relative risk 2.00, 95% CI 1.11–3.57, P=.03) and anemia (relative risk 2.30, 95% CI 1.26–4.22, P=.005) at their baseline visit than women who returned to baseline functional status (Table 2). On multivariable logistic regression after controlling for surgeon, procedures, and complication severity, history of weight loss was associated with a 2.44 increased risk (95% CI 1.26–4.71) and anemia was associated with a 2.72 increased risk (95% CI 1.29–5.75) of not returning to baseline functional status.
The median (range) length of stay in a medical facility for the 127 women was 3 (1–15) days. The median length of stay for women who did not return to baseline functional status (3 days, range 1–9 days) was similar to women who did return to baseline functional status (3 days, range 0–15 days, P=.76).
On univariable linear regression, preoperative functional status markers significantly associated with increased length of stay were American Society of Anesthesiologists class III (P=.004), number of functional limitations (P=.05), weight loss of 10 or more pounds (P=.007), and presence of a Dindo grade 3 complication (P<.001). On multivariable analysis, after adjusting for confounding variables (type of surgical procedure, surgeon, and complication severity), preoperative functional status markers significantly associated with longer length of stay were American Society of Anesthesiologists class III and weight loss (P<.05) (Table 3).
Our study shows that functional limitations are useful markers for predicting postoperative outcomes after surgery. Specifically, presence of a preoperative limitation predicts an increase in postoperative functional limitations and longer length of stay after surgery. Recent weight loss of 10 or more pounds and anemia also increase likelihood of failure to return to baseline functional status at 12 weeks, whereas weight loss and American Society of Anesthesiologists class III increase hospital length of stay.
Previous studies9,27 have shown decreases in quality of life in women up to 6 weeks after surgery but quality of life improved and was above baseline at 24 weeks postoperatively. Six months may be a long time for high-functioning older women to anticipate surgical recovery. Data on trajectory of postoperative recovery between 6 weeks and 6 months can help women with postoperative planning. The present study fills a gap in the literature on functional status outcomes between 6 weeks and 6 months. Our study shows that most women return to baseline function as early as 12 weeks after surgery. For women who fail to return to baseline functional status by 12 weeks, several preoperative functional status markers can identify women at higher risk for slower recovery after surgery; eg, American Society of Anesthesiologists class III, history of recent weight loss more than 10 pounds, and preoperative anemia. Surgeons can use this information not only to prepare women for potentially longer hospital stays and postoperative recovery, but also to intervene preoperatively to optimize surgical recovery.
American Society of Anesthesiologists class emerged as a clinically useful predictor of postoperative functional status. In our study, American Society of Anesthesiologists class was measured by the anesthesiologist immediately before surgery. The American Society of Anesthesiologists classification system is simple, takes only a few minutes to administer, and includes an assessment of comorbidity and physical status.28 For example, American Society of Anesthesiologists class II describes a patient with mild to moderate systemic disease and distress after walking up one flight of stairs, whereas class III describes a patient with severe systemic disease and having to stop while climbing a flight of stairs. Given the usefulness of American Society of Anesthesiologists class in predicting postoperative outcomes, clinicians could potentially consider determining the American Society of Anesthesiologists class in the preoperative clinic to counsel women regarding their anticipated postoperative recovery. Surgeons could also use the American Society of Anesthesiologists class to identify patients who require treatment of their comorbidities and optimization of their functional status in collaboration with a primary care physician or geriatrician.
Two frailty markers, history of recent weight loss and anemia, emerged as predictors of worse postoperative functional outcomes. Although the mean body mass index of patients who failed to return to baseline functional status was higher than that of women who did return to baseline status, a history of recent weight loss was a marker of failure to return to baseline functional status and prolonged length of stay. Both weight loss and low albumin levels are markers of chronic under nutrition and frailty in elderly patients.16,29 This may potentially explain the mechanism through which weight loss is associated with worse postoperative outcomes. Similarly, anemia has also been identified as a marker of frailty and emerged as predictor of worse outcomes in our study. The presence of these markers will alert both surgeons and patients that full surgical recovery may require longer than 3 months.
Strengths of our study include its prospective design and use of self-reported measures of functional status that can easily be administered in the clinic during routine preoperative assessment. Such self-reported measures of functional status have demonstrated moderate to high correlation with objective assessments.30
Our limitations include a missing data rate of 13.4%. It is possible that women with worse outcomes preferentially did not return for postoperative follow-up; however, the length of stay and number of postoperative complications in patients with missing data were not significantly higher than those who contributed completed data. Our follow-up period was also short (12 weeks). It is likely that with longer follow-up, the majority of the women would have returned to baseline functional status and preoperative functional status markers may be less useful for predicting long-term outcomes after surgery. We may also have been underpowered to look at specific functional limitations in a healthier community-dwelling population because our sample size calculation was based on a more frail elderly population. Despite these limitations, our study suggests that several preoperative functional status markers are clinically useful for predicting postoperative functional outcomes in older women undergoing surgery for POP.
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Activities of Daily Living Assessment
Please rate your need for assistance with performing the following activities by checking the appropriate box.
Functional Health Scale
We are interested in how much difficulty people have with various activities because of a health or physical problem. Exclude any difficulties that you expect to last less than 3 months.