Long-term change in respiratory function following spinal cord injury.

STUDY DESIGN: Retrospective study. OBJECTIVES: To model the effect of time since injury on longitudinal respiratory function measures in spinal cord injured-individuals and to investigate the effect of patient characteristics. SETTING: A total of 173 people who sustained a spinal cord injury between 1966 and April 2013 and who had previously participated in research or who underwent clinically indicated outpatient respiratory function tests at the Austin Hospital in Melbourne, Australia, were included in the study. At least two measurements over time were available for analysis in 59 patients. METHODS: Longitudinal data analysis was performed using generalised linear regression models to determine changes in respiratory function following spinal cord injury from immediately post injury to many years later. Secondly, we explored whether injury severity, age, gender and body mass index (BMI) at injury altered the time-dependent change in respiratory function. RESULTS: The generalised linear regression model showed no significant change (P=0.276) in respiratory function measured in (forced) vital capacity ((F)VC) after the spinal cord injury. However, significant (P<0.05) differences in respiratory function over time were found when categorising age and BMI. CONCLUSION: This clinical cohort with long-term, repeated measurements of respiratory function showed no significant overall change in respiratory function over 23 years. However, a decline in respiratory function over time was observed in subgroups of individuals older than 30 years at the onset of injury and in those with a BMI>30 kg m(-2).

Validation of the Dutch clinical prediction rule for ambulation outcomes in an inpatient setting following traumatic spinal cord injury.

STUDY DESIGN: Retrospective study. OBJECTIVES: To determine the accuracy of a previously described Dutch clinical prediction rule for ambulation outcome in routine clinical practice. SETTING: Adult (⩾18 years) patients who were admitted to the Austin Hospital with a traumatic spinal cord injury between January 2006 and August 2014. METHODS: Data from medical records were extracted to determine the score of the Dutch clinical ambulation prediction rule proposed by van Middendorp et al. in 2011. A receiver-operating characteristics (ROC) curve was generated to investigate the performance of the prediction rule. Univariate analyses were performed to investigate which factors significantly influence ambulation after a traumatic spinal cord injury. RESULTS: The area under the ROC curve (AUC) obtained during the current study (0.939, 95% confidence interval (CI) (0.892, 0.986)) was not significantly different from the AUC from the original Dutch clinical prediction model (0.956, 95% CI (0.936, 0.976)). Factors that were found to have a significant influence on ambulation outcome were time spent in the ICU, number of days hospitalised and injury severity. Age at injury initially showed a significant influence on ambulation however, this effect was not apparent after inclusion of the 24 patients who died due to the trauma (and therefore did not walk after their injuries). CONCLUSION: The Dutch ambulation prediction rule performed similarly in routine clinical practice as in the original, controlled study environment in which it was developed. The potential effect of survival bias in the original model requires further investigation.

Subjective sleep disturbances and quality of life in chronic tetraplegia.

STUDY DESIGN: This is a cross-sectional survey. OBJECTIVES: The objective of this study was to evaluate the subjective sleep disturbances and quality of life in chronic tetraplegia. SETTING: This study was conducted in a community sample from Victoria, Australia. METHODS: People with tetraplegia were mailed a survey battery including the following: demographic questions; Karolinska Sleepiness Scale (KSS); Basic Nordic Sleepiness Questionnaire; Functional Outcomes of Sleep Questionnaire (FOSQ); Multivariate Apnoea Prediction Index and Assessment of Quality of Life (AQoL) Questionnaire. Scores were compared with the best available normative data. RESULTS: A total of 163 of 424 (38%) surveys were returned (77% male; 39% sensory and motor complete; mean age±s.d.=46±14 years; mean years since injury=11±8 years). The AQoL health utility score (0.31±0.29) was significantly lower than published population norms. FOSQ total (17.55±2.57) and KSS (3.93±2.27) scores were no different from the best available population data. People with tetraplegia reported worse sleep habits, symptoms and quality than a normal population, as indicated on 17 of 21 questions on the Basic Nordic Sleep Questionnaire. Multivariate analysis found that greater injury severity (coefficient (95% CI)=0.14 (0.10, 0.18)), increasing age (-0.004 (-0.008, -0.001)) and worse sleep symptoms (-0.005 (-0.009, -0.0003)) were all significantly associated with reduced quality of life. CONCLUSION: People with chronic tetraplegia experience more subjective sleep problems and worse quality of life than their able-bodied counterparts. Quality of life is related to injury severity, age and sleep symptoms. Treating the sleep disorders experienced by people living with tetraplegia has the potential to improve their health and well-being.

Developing a spinal cord injury research strategy using a structured process of evidence review and stakeholder dialogue. Part III: outcomes.

STUDY DESIGN: Focus Group. OBJECTIVES: To develop a unified, regional spinal cord injury (SCI) research strategy for Australia and New Zealand. SETTING: Australia. METHODS: A 1-day structured stakeholder dialogue was convened in 2013 in Melbourne, Australia, by the National Trauma Research Institute in collaboration with the SCI Network of Australia and New Zealand. Twenty-three experts participated, representing local and international research, clinical, consumer, advocacy, government policy and funding perspectives. Preparatory work synthesised evidence and articulated draft principles and options as a starting point for discussion. RESULTS: A regional SCI research strategy was proposed, whose objectives can be summarised under four themes. (1) Collaborative networks and strategic partnerships to increase efficiency, reduce duplication, build capacity and optimise research funding. (2) Research priority setting and coordination to manage competing studies. (3) Mechanisms for greater consumer engagement in research. (4) Resources and infrastructure to further develop SCI data registries, evaluate research translation and assess alignment of research strategy with stakeholder interests. These are consistent with contemporary international SCI research strategy development activities. CONCLUSION: This first step in a regional SCI research strategy has articulated objectives for further development by the wider SCI research community. The initiative has also reinforced the importance of coordinated, collective action in optimising outcomes following SCI.

A systematic review and meta-analysis of the effects of respiratory muscle training on pulmonary function in tetraplegia.

STUDY DESIGN: Systematic reviewObjectives:To determine the effect of respiratory muscle training (RMT) on pulmonary function in tetraplegia. METHODS: A comprehensive search of the research literature included MEDLINE, EMBASE, CINAHL, ISI Web of Science, PubMed, the relevant Cochrane and clinical trials registers and hand-searching the reference lists of appropriate papers. There was no language restriction. All randomised controlled trials that involved RMT vs. control were considered for inclusion. Two reviewers independently selected articles for inclusion, evaluated the methodological quality and extracted data. Additional information was sought from the authors when necessary. RESULTS: Eleven studies (212 participants) were included. A significant benefit of RMT was revealed for five outcomes: vital capacity (mean difference (95% confidence interval))=0.41(0.17-0.64) l, maximal inspiratory pressure=10.66(3.59, 17.72) cmH2O, maximal expiratory pressure=10.31(2.80-17.82) cmH2O, maximum voluntary ventilation=17.51(5.20, 29.81) l min(-1) and inspiratory capacity=0.35 (0.05, 0.65) l. No effect was found for total lung capacity, peak expiratory flow rate, functional residual capacity, residual volume, expiratory reserve volume or forced expiratory volume in 1 second. CONCLUSION: RMT increases respiratory strength, function and endurance during the period of training. Further research is needed to determine optimum dosages and duration of effect. This article is based in part on a Cochrane review published in the Cochrane Database of Systematic Reviews (CDSR) 2013, DOI:10.1002/14651858.CD008507.pub2. Cochrane reviews are regularly updated as new evidence emerges and in response to feedback, and the CDSR should be consulted for the most recent version of the review.

Sleep disruption in tetraplegia: a randomised, double-blind, placebo-controlled crossover trial of 3 mg melatonin.

STUDY DESIGN: Randomised, double-blind, placebo-controlled crossover trial of melatonin supplementation to people with complete tetraplegia. OBJECTIVES: To investigate the effect that 3 mg melatonin supplementation has on objective and subjective sleep, quality of life and mood of people living with complete tetraplegia. SETTING: Austin Hospital Sleep Laboratory and participants' homes, Melbourne, Victoria, Australia. METHODS: Two week run-in followed by 3 week nightly administration of 3 mg melatonin or placebo, 2-week washout and further 3 week administration of the opposite treatment. Four testing sessions were conducted; the last nights of the run-in, treatment and washout periods. Testing sessions involved recording full polysomnography, completing a questionnaire battery and collecting urine and blood samples. The questionnaires assessed mood, sleep symptoms and health-related quality of life, and the urine and plasma samples assayed 6-sulphatoxymelatonin (aMT6s) and melatonin levels, respectively. A sleep diary was completed throughout the study. RESULTS: Eight participants (mean (s.d.): age 49.5 years (16), postinjury 16.9 years (7.1)) were recruited in which seven concluded the protocol. Endogenous-circulating melatonin was significantly higher (P < or = 0.01) following melatonin (urine: 152.94 µg h(-1) (74.51), plasma: 43,554.57 pM (33,527.11)) than placebo (urine: 0.86 µg h(-1) (0.40), plasma: 152.06 pM (190.55)). Subjective sleep improved significantly following melatonin specifically for duration of sleep per night and psychological wellbeing. Objective sleep showed a significant increase in light sleep with melatonin, with all other sleep parameters being unchanged. CONCLUSION: These results suggest that increasing melatonin in people with complete tetraplegia is beneficial, especially for subjective sleep. Investigation of the pharmacokinetics of melatonin metabolism in this population is warranted. SPONSORSHIP: This project is proudly supported by the Transport Accident Commission.

Continuous positive airway pressure requirements in patients with tetraplegia and obstructive sleep apnoea.

STUDY DESIGN: Clinic-based retrospective case-control study. OBJECTIVES: To compare continuous positive airway pressure (CPAP) requirements between patients with tetraplegia and able-bodied patients with obstructive sleep apnoea (OSA). SETTING: Melbourne, Australia. METHODS: Diagnostic and CPAP titration polysomnograms of 219 able-bodied, and 25 patients with tetraplegia and OSA were compared for apnoea hypopnoea index (AHI) and CPAP levels required to effectively treat OSA. Demographics and body mass index (BMI) were obtained for each patient. ASIA score and injury date were obtained for patients with tetraplegia. RESULTS: There was no significant difference in AHI (P=0.102) between the two groups; however, able-bodied patients were significantly older (P=0.003), required significantly higher levels of CPAP to control their OSA (P<0.001) and had higher BMIs (P=0.009) than patients with tetraplegia. In the tetraplegia group, there was no significant correlation between AHI and effective CPAP (r=0.022, P=0.92) or between AHI and BMI (r=-0.196, P=0.35). There was a significant correlation between effective CPAP and BMI (r=0.411, P=0.041). Among able-bodied patients, over two-thirds (68.8%) required 10-16 cm H(2)0 to control their OSA and nearly one-third required over 16 cm H(2)0. In contrast, over two-thirds (68.8%) in the tetraplegia group required less than 10 cm H(2)0 of CPAP to control their OSA. CONCLUSION: This retrospective study suggests that OSA patients with tetraplegia require significantly less CPAP to treat their OSA at any given AHI than those who are able-bodied. This suggests that additional unknown factors may contribute to the high prevalence of OSA in tetraplegia.

The feasibility of using auto-titrating continuous positive airway pressure to treat obstructive sleep apnoea after acute tetraplegia.

STUDY DESIGN: A prospective cohort with acute tetraplegia. OBJECTIVES: Obstructive sleep apnoea (OSA) is common within weeks of tetraplegia. This study aimed at determining the feasibility of auto-titrating continuous positive airway pressure (CPAP) to treat OSA after acute tetraplegia. SETTING: The Victorian Spinal Cord Service, Melbourne, Australia. METHODS: Participants underwent full, portable polysomnography. Those with an apnoea hypopnoea index of more than 10 events per hour were defined as having OSA and were offered treatment with CPAP. Treatment adherence was objectively monitored, and measures of quality of life, sleepiness and functional outcomes were determined at enrollment and 3 months later at study conclusion. RESULTS: A total of 44 patients were admitted to our Spinal Cord Service over 9 months, and 19 participated. Fourteen of them had OSA and seven were adherent with therapy for 3 months. Compared with those who did not have OSA, and with those with OSA who were not adherent with CPAP, those who adhered to CPAP were older (mean (s.d.) age 54 years (13) versus non-adherent 28 years (15) and no OSA 29 years (10)) and heavier (body mass index (BMI) 32.5 (11.7), 24.1 (3.7) and 20.6 (3.1), respectively). CPAP-adherant patients and those without OSA showed a 50% or greater improvement in their state sleepiness over the 3 months. Patients with OSA who did not tolerate CPAP had no improvement in sleepiness. CONCLUSION: Auto-titrating CPAP is a feasible treatment for OSA in acute tetraplegia. Intensive clinical support was required initially, and a tolerance of therapy for at least 4 h for one of the first 3 days was predictive of good CPAP usage. SPONSORSHIP: Transport Accident Commission.

Pharmacological and clinical aspects of antiepileptic drug use in the elderly.

In this article, epidemiological and clinical aspects related to the use of antiepileptic drugs (AEDs) in the elderly are highlighted. Studies have shown that people with epilepsy receiving AED treatment show important deficits in physical and social functioning compared with age-matched people without epilepsy. To what extent these deficits can be ascribed to epilepsy per se or to the consequences of AED treatment remains to be clarified. The importance of characterizing the effects of AEDs in an elderly population is highlighted by epidemiological surveys indicating that the prevalence of AED use is increased in elderly people, particularly in those living in nursing homes. Both the pharmacokinetics and the pharmacodynamics of AEDs may be altered in old age, which may contribute to the observation that AEDs are among the drug classes most commonly implicated as causing adverse drug reactions in an aged population. Age alone is one of several contributors to alterations in AED response in the elderly; other factors include physical frailty, co-morbidities, dietary influences, and drug interactions. Individualization of dosage, avoidance of unnecessary polypharmacy, and careful observation of clinical response are essential for an effective and safe utilization of AEDs in an elderly population.

The use of follow-up chest roentgenograms among hospitalized patients.

Follow-up chest roentgenograms are a commonly performed test. We prospectively evaluated their diagnostic and therapeutic influence at a tertiary care teaching hospital. When a follow-up chest roentgenogram was ordered, physicians indicated their reason for ordering the test, the likelihood that the roentgenogram would show changes, and expected alterations in therapy. After the roentgenogram was obtained, physicians described the help provided by the roentgenogram and what changes in therapy were performed. Using receiver operating characteristic curves, we have shown that physicians have difficulty in predicting which roentgenograms will show important changes. Unexpected findings are frequent (25.4%) and highly valued by the physician. Fifty-seven percent of these roentgenograms had a definite or possible influence on patient treatment. Further studies are indicated to define when follow-up chest roentgenograms are likely to be of benefit.

Evaluating pressure ulcer occurrence in long-term care: pitfalls in interpreting administrative data.

Administrative databases for long-term care frequently collect information on fixed dates of the calendar year, rather than for entire episodes of care. Patients discharged or dying prior to an evaluation date are lost to follow-up. We used one such database, the VA Patient Assessment File, to examine pressure ulcer occurrence in long-term care. Clinical studies have established that most pressure ulcers develop during the first several weeks following admission. In these data, however, pressure ulcer development was less common in patients assessed within 2 months following admission, as compared to those examined at 3 to 6 months. This finding appears to be related to the selective discharge of patients, which makes these patient populations noncomparable. These results highlight that care must be exercised when interpreting results obtained from such administrative data.

The short-term outcome of pressure sores.

Patients with pressure sores have been observed to have a poor prognosis. The short-term outcome of pressure sores at a long-term care hospital was therefore evaluated. Medical records on the 301 admissions to this hospital over a 13-month period were reviewed. One hundred patients (33%) had a pressure sore present on admission. Using ordinary therapies, 79% of these pressure sores improved and 40% completely healed during the 6-week follow-up period. Remaining bed- or chair-bound was the sole patient characteristic associated with a failure of the pressure sore to improve. Mortality rates were significantly increased in patients with a pressure sore present on admission (relative risk [RR] = 1.9), in patients who developed a new sore (RR = 3.1), and in patients in whom the pressure sore failed to improve (RR = 3.3). However, the pressure sores did not appear to be the direct cause of this increased mortality. These data suggest that the majority of pressure sores encountered at a long-term care hospital can be successfully managed in this setting. Although patients with pressure sores have an increased mortality rate, this is most likely due to coexisting medical conditions.

Risk factors for pressure sores. A comparison of cross-sectional and cohort-derived data.

The purpose of this study was to identify prospectively risk factors for pressure sores and to compare these results with a cross-sectional analysis in the same population. Medical records on all admissions to a chronic care hospital over a 13-month period were reviewed. Data on potential risk factors were abstracted from the initial history, physical examination, nursing assessment, and laboratory studies. Pressure sore status on admission and at three weeks was determined from a standardized from completed on all patients with a score. The cross-sectional analysis was performed by comparing patients with and without a pressure sore at the time of admission. The cohort analysis used patients initially without a pressure sore and monitored for a new sore at three weeks. Factors associated with pressure sores on univariate testing were entered into a stepwise logistic regression model. One hundred of the 301 admissions presented with a pressure sore. Factors significantly associated with the presence of a sore were altered level of consciousness (OR = 4.1), bed- or chair-bound (OR = 2.4), impaired nutritional intake (OR = 1.9), and hypoalbuminemia (OR = 1.8 for 10 mg/mL decrease). Of the 185 patients without a pressure sore, 20 (10.8%) developed a sore. Factors significantly associated with the development of a new pressure sore were a history of cerebrovascular accident (OR = 5.0), bed- or chair-bound (OR = 3.8), and impaired nutritional intake (OR = 2.8). Neither urinary nor fecal incontinence, nor the presence of hypoalbuminemia, was associated with sore development. We have prospectively identified risk factors for pressure sores.(ABSTRACT TRUNCATED AT 250 WORDS)

Geriatric syndromes as outcome measures of hospital care: can administrative data be used?

OBJECTIVE: To determine how often hospital administrative databases capture the occurrence of two common geriatric syndromes, pressure ulcers and incontinence. DESIGN: Retrospective comparison of a nursing home and hospital database. SETTING: Department of Veterans Affairs (VA) hospitals. PARTICIPANTS: All patients between 1992 and 1996 discharged from VA acute medical care and admitted to a VA nursing home. MEASUREMENTS: The presence of incontinence or a pressure ulcer (stage 2 or larger) on admission to the nursing home was determined. Hospital discharge diagnoses were then reviewed to determine whether these conditions were recorded. The effect of ulcer stage, total number of discharge diagnoses, and temporal trends on the recording of these conditions in discharge diagnoses was also noted. RESULTS: There were 17,004 admissions to nursing homes from acute care in 1996; 12.7% had a pressure ulcer and 43.4% were incontinent. Among these patients with a pressure ulcer, the hospital discharge diagnosis listed an ulcer in 30.8% of cases, and incontinence was included correctly as a discharge diagnosis in 3.4%. While deeper pressure ulcers were more likely to be recorded than superficial ulcers (P < .01), nearly 50% of stage 4 ulcers were not listed among hospital discharge diagnoses. Patients with more discharge diagnoses were more likely to record both conditions correctly. From 1992 to 1996, small but significant (P = .001) improvements were noted in the correct recording of these geriatric syndromes as discharge diagnoses. CONCLUSIONS: The occurrence of pressure ulcers and incontinence cannot be determined from hospital administrative databases and should not be used as outcomes when measuring quality of care among hospitalized patients.

Do-not-resuscitate orders at a chronic care hospital.

Do-not-resuscitate (DNR) orders have become an accepted part of medical practice. While these orders have been extensively evaluated in acute care hospitals, little is known about their use in the long-term care setting. We reviewed the medical records of all admissions to a chronic care hospital over a 13-month period, collecting data on selected patient characteristics, use of DNR orders, and patient outcomes during the 6-week period following admission. Fifty-eight of the 301 patients (19.3%) had a DNR order written. Patients' families were involved predominantly in the DNR decision in 73% of the cases while patients themselves were involved in only 18%. Physicians made the decision unilaterally in 6% of the cases. Patients' functional status rather than specific diagnoses predicted the use of DNR orders. Patients with DNR orders were twice as likely to receive new intravenous therapies than patients without those orders (71% vs 33%, P less than 0.01) and four times as likely to die (38% vs 9%, P less than 0.01). They were no more likely to be transferred emergently to an acute care hospital (5% vs 9%, P greater than 0.2). We conclude that DNR orders are not infrequently used, and physicians rarely make the decision unilaterally. Patients with DNR orders have a high likelihood of dying and are infrequently transferred to acute care facilities.

Predictors of pressure ulcer healing among long-term care residents.

OBJECTIVES: To identify predictors of pressure ulcer healing among long-term care residents. DESIGN: A retrospective cohort study. SETTING: Department of Veterans Affairs (VA) long-term care facilities. PARTICIPANTS: All long-term care residents with a pressure ulcer on April 1, 1993, who remained institutionalized as of October 1, 1993. Patients and pressure ulcer status were identified from the Patient Assessment File, a VA administrative database. MEASUREMENTS: Pressure ulcers were considered healed if patients were without an ulcer on October 1, 1993. Predictors of pressure ulcer healing were selected from among patient characteristics in the Patient Assessment File. RESULTS: Pressure ulcers were present in 7.7% of the long-term care residents institutionalized as of April 1, 1993. Among the 819 pressure ulcer patients remaining institutionalized as of October 1, 1993, ulcers had healed in 442 (54.0%). Seventy-two percent of patients with Stage 2 ulcers were ulcer-free at 6 months, compared with 45.2% of patients with Stage 3 ulcers and 30.6% of those with Stage 4 ulcers (P < .001). Significant (P < .05) independent predictors of healing included pressure ulcer size (Odds ratio (OR) = 5.2 for Stage 2 ulcers, OR = 1.5 for Stage 3 ulcers), older age (OR = 1.5), and receiving rehabilitation services (OR = 1.3 for each additional type of therapy). Both immobility (OR = .3) and incontinence (OR = .7) were associated with ulcers not healing. CONCLUSIONS: Most Stage 2 pressure ulcers, and many larger ulcers encountered in long-term care settings will heal. Baseline patient characteristics are important predictors of healing. Interventions may then be targeted at patients whose ulcers are unlikely to heal, and observed facility performance may be compared with expected outcomes.

Are we improving the quality of nursing home care: the case of pressure ulcers.

BACKGROUND: There are widespread concerns regarding the quality of nursing home care and whether care is improving. We evaluated a large provider of nursing home care to determine whether risk-adjusted rates of pressure ulcer development have changed. METHODS: We used the Minimum Data Set to study National HealthCare Corporation nursing homes from 1991 through 1995. Rates of pressure ulcer development were calculated for successive 6-month periods by determining the proportion of residents initially ulcer-free having a stage 2 or larger pressure ulcer on subsequent assessments. Rates were risk-adjusted for patient characteristics. The proportion of new ulcers that were deep (stages 3 or 4) were also calculated. RESULTS: We examined risk-adjusted rates of pressure ulcer development based on 144,379 observations of 30,510 residents at 107 nursing homes. The number of observations per 6-month period ranged from 11,041 to 15,805. Between 1991 and 1995, there was a significant (P<.05) rate decline of more than 25%. Additionally, the proportion of new ulcers that were stages 3 or 4 declined from 30 to 22% (P<.01). CONCLUSIONS: Nursing homes showed significant improvement in the quality of pressure ulcer preventive care from 1991 to 1995.

Evaluation of a risk-adjustment model for pressure ulcer development using the Minimum Data Set.

OBJECTIVE: To validate a previously derived risk-adjustment model for pressure ulcer development in a separate sample of nursing home residents and to determine the extent to which use of this model affects judgments of nursing home performance. DESIGN: Retrospective observational study using Minimum Data Set (MDS) data from 1998. SETTING: A large, for-profit, nursing home chain. PARTICIPANTS: Twenty-nine thousand and forty observations were made on 13,457 nursing home residents who were without a pressure ulcer on an index assessment. MEASUREMENTS: We used logistic regression in our validation sample to calculate new coefficients for the 17 previously identified predictors of pressure ulcer development. Coefficients from this new sample were compared with those previously derived. Expected rates of pressure ulcer development were determined for 108 nursing homes. Unadjusted and risk-adjusted rates of pressure ulcer development from these homes were also calculated and outlier identification using these two approaches was compared. RESULTS: Predictors of pressure ulcer development in the derivation sample generally showed similar effects in the validation sample. The model c-statistic was also unchanged at 0.73, but it was not calibrated as well in the validation sample. On applying the model to the nursing homes, expected rates of ulcer development ranged from 1.1% to 3.2% (P <.001). The observed rates ranged from 0% to 12.1% (P <.001). There were 12 outliers using unadjusted rates and 15 using adjusted performance. Ten nursing homes were identified as outliers using both approaches. CONCLUSIONS: Our MDS risk-adjustment model for pressure ulcer development performed well in this new sample. Nursing homes differ significantly in their expected rates of pressure ulcer development. Outlier identification also differs depending on whether unadjusted or risk-adjusted performance is evaluated.