Estimating the distribution of quality-adjusted life with censored data.
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Cardiovascular Agents↗
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Normative data for the Mattis Dementia Rating Scale.
Age-adjusted normative data are presented for persons over age 55 on the Mattis Dementia Rating Scale. Additional adjustment for the effect of education on test performance is also provided. These data were collected as part of Mayo's Older Americans Normative Studies (MOANS) in a continuing effort to develop age-appropriate norms for older persons on commonly used neuropsychological tests. The normative data presented here should prove more useful in characterizing the presence and severity of general cognitive dysfunction than currently available norms. Limitations and unique features of MOANS normative data are also discussed.
Aged↗
Risk adjustment in studies using administrative data.
Administrative data are increasingly used to evaluate service use and cost of treatments in "real world" settings. However, the degree to which administrative data can be used to risk-adjust for differences between nonrandomized groups receiving different treatments has not been studied. This study used data from a large randomized trial to determine whether administrative data describing previous utilization and cost are as good as clinical data in predicting future resource utilization and cost. Clinical data (symptoms, quality of life, pharmacological side effects) and administrative data (inpatient utilization and total cost) were obtained from a large randomized clinical trial comparing clozapine and haloperidol. The combination of administrative measures prior to randomization was the best predictor in a multiple regression model of service use in the year after randomization (adjusted r2 = 0.27-0.31). Models using administrative data alone predicted 24 to 28 percent of the variance of service use and costs, while clinical data predicted only 6 to 7 percent of the variation in the same dependent variables. In this analysis, administrative data about previous utilization and costs were far more successful than clinical data alone at predicting future utilization and costs and are therefore likely to be better risk adjusters in studies with nonrandomized comparison groups.
Adult↗
Geographic trends in prostate cancer mortality: an application of spatial smoothers and the need for adjustment.
Prostate cancer mortality among whites and nonwhites in U.S. counties are analyzed for geographic effects. To better visualize geographical effects, the data are smoothed with a bivariate smoother using age-specific rates. Among nonwhites, an important explanatory variable is the proportion of African Americans. A relationship between the mortality rate and this variable is derived, and the data are adjusted for this variable using this relationship. When the rates are adjusted for age only, among whites there is a north-south gradient: rates are higher in the north, lower in the south. Among nonwhites, the gradient runs east to west: higher in the east, lower in the west. The latter gradient disappears when the rates are further adjusted for African Americans. The study reveals the importance of both smoothing the data to visualize patterns in geography and adjusting the data for an important variable to identify underlying patterns. The additional adjustment permits the identification of other areas of the country with elevated or depressed rates.
Adult↗
The use of models for estimating overall incidence trend.
Several approaches to evaluate an overall trend including Registries with different length of activity with a defined period of time have been evaluated in the cancer trend study of the Italian Network of Cancer Registries (AIRT). The study used the nine Registries of the pool AIRT in the period 1986-1997. Data for 1986-1993 from the Registry of Ragusa have been excluded to simulate the inclusion of a Registry with partial observation. Four different approaches have been used: Golden standard (GS) as a weighted mean of the observed standardised (European population) rates in the whole pool AIRT; 2) Raw trend (TG) computed with partial data of Ragusa; 3) Model trend (TM) estimated by means of a log-linear model including age, registry and period as independent variables and applied on the partial data set; Adjusted trend (TC) computed on complete data for eight Registries, observed 1994-1997 data of Ragusa and estimated data for Ragusa for 1986-1993 computed by (3) model. The trend estimates, as estimated annual percent change of the standardised rates (EAPC) have been compared with GS. The results of this preliminary analysis do not recommend the use of raw trend and indicate adjusted trend as the most reliable method for trend estimate.
Algorithms↗
Surgical treatment of severe obesity with a low-pressure adjustable gastric band: experimental data and clinical results in 625 patients.
OBJECTIVE: To evaluate the use of a low-pressure gastric band in the treatment of severe obesity in a prospective study. SUMMARY BACKGROUND DATA: Gastric banding for severe obesity has been associated with erosion and perforation of the stomach. The Swedish adjustable gastric band (SAGB) has been proposed as a low-pressure device. METHODS: From January 1998 to October 2001, 625 patients underwent laparoscopic SAGB. Median age was 36 years, and 80.4% of patients were female. Median preoperative body mass index (BMI) was 40. Previous upper abdominal surgery was reported in 36 (6%) patients. A five-trocar technique was used without a calibration balloon. RESULTS: Median follow-up was 19.5 months. All patients were treated laparoscopically with a median operating time of 80 minutes. Conversion was necessary in two patients (0.3%): one trocar injury of the mesentery and one esophageal perforation. Median hospital stay was 3 days; there were no 30-day deaths. Early morbidity was present in 27 patients (4.3%). Late band reoperation was necessary in 49 patients (7.8%). Indications for reoperation were band slippage or pouch dilation, acute total dysphagia, and band leakage or malfunction. Median excess weight loss was 45.8%, 49.9%, and 47.4% after 1, 2, and 3 years, respectively, with a measurable beneficial effect on arterial hypertension, sleep apnea syndrome, and diabetes control. CONCLUSIONS: SAGB is a safe and effective new method in the management of severe obesity. Long-term follow-up (>3 years) is necessary to confirm its effectiveness and safety.
Adult↗
Continuous assessment and improvement in quality of care. A model from the Department of Veterans Affairs Cardiac Surgery.
OBJECTIVE: The authors organized the Department of Veterans Affairs (VA) Continuous Improvement in Cardiac Surgery Study (CICSS) to provide risk-adjusted outcome data for the continuous assessment and improvement of quality of care for all patients undergoing cardiac surgery in the VA. BACKGROUND: The use of risk-adjusted outcomes to monitor quality of health care has the potential advantage over consensus-derived standards of being free of preconceived biases about how health care should be provided. Monitoring outcomes of all health care episodes, as opposed to review of selected cases (e.g., adverse outcomes), has the advantages of greater statistical power, the opportunity to compare processes of care between good and bad outcomes, and the positive psychology of treating all providers equally. These two concepts, together with a pre-existing peer committee (the VA Cardiac Surgery Consultants Committee) to review, interpret, and act on the risk-adjusted outcome data, form the primary design considerations for CICSS. METHODS: Patient-level risk and outcome (operative mortality and morbidity) data are collected prospectively on each of the approximately 7000 patients undergoing cardiac surgery in the VA each year. These outcomes, adjusted for patient risk using logistic regression, are provided every 6 months to each cardiac surgery program and to a national peer review committee for internal and external quality assessment and improvement. RESULTS: For the most recent 12-month period with complete data collection, observed-to-expected (O/E) ratios ranged from 0.2 to 2.2, with eight centers falling outside of the 90% confidence limits for an O/E ratio equaling 1.0. The O/E ratio for all centers has fallen by 14% over the 4.5-year period of this program (p = 0.06). CONCLUSIONS: A large-scale, low-cost program of continuous quality improvement using risk-adjusted outcome is feasible. This program has been associated with a decrease in risk-adjusted operative mortality.
Cardiac Surgical Procedures↗
The missing ages: adjusting for digit preference.
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Africa↗
Interpreting hospital mortality data. The role of clinical risk adjustment.
This study uses national Medicare data as well as data that were abstracted to calibrate the Medicare Mortality Predictor System to assess the usefulness of a risk adjustment system in interpreting hospital mortality rates. The majority of variation in annual hospital death rates for the four conditions studied (stroke, pneumonia, myocardial infarction, and congestive heart failure) is chance variability that results from the relatively small numbers of patients treated in most hospitals in a year. For hospitals in the highest and lowest quartiles of observed death rates, the difference between observed rates and those predicted by the Medicare Mortality Predictor System is not quite on third smaller than the difference between observed rates and unadjusted national rates. Risk adjustment methods do not show whether the unexplained difference in mortality rates results from differences in effectiveness of care or unmeasured differences in patient risk at the time of admission. Risk-adjusted mortality rates, therefore, should be supplemented by review of the actual care rendered before conclusions are drawn regarding effectiveness of care.
Aged↗
Social adjustment in three cultures: data from families affected by chronic blood disorders. A sibling study.
This study explores the rate of psychosocial dysfunction in affected and unaffected children from families with haemophilia or beta-thalassaemia, as part of a cross-sectional, multicentre study into the resilience of 115 families with blood disorders. Sociodemographic and developmental data were collected from the parents using a standardized and semi-structured interview format, and medical data were obtained from the clinician. The children's social functioning over the year prior to the assessment was assessed with The Social Adjustment Scale adapted for school-aged children. Children with beta-thalassaemia showed significantly higher rates of social dysfunction than their unaffected siblings or children with haemophilia and their siblings. Older children showed significantly higher social dysfunction at school. The high rate of social dysfunction in children with beta-thalassaemia compared with unaffected siblings is likely to have a basis in the negative experiences associated with their medical problems. In contrast, the therapeutic advances in haemophilia allows boys to lead an almost normal life. Overall, the rates of social dysfunction in families with both these disorders proved commoner than reported in population surveys, but with the unavailability of local population controls, caution needs to be exercised in the interpretation of this finding.
Adolescent↗
Risk adjustment for complications of hysterectomy: limitations of routinely collected administrative data.
OBJECTIVE: We sought to determine the utility of routinely collected administrative data for risk adjustment for complications of hysterectomy. STUDY DESIGN: Using abstracted discharge data on 107, 648 women undergoing hysterectomy in North Carolina from 1988 through 1994, we constructed logistic regression models for the prediction of medical and surgical complications incorporating coded demographic, diagnostic, and procedural data. RESULTS: The overall complication rate was 16%, with surgical complications (11.8%) more common than medical complications (6.7%). Hysterectomy type, teaching hospital status, patient age >/=65 years, and insurance status of Medicaid or no insurance were significantly associated with both medical and surgical complication risk, as were procedures performed for cancer or pregnancy complications. Models that incorporated coded comorbidity were better predictors of medical complications (C = 0.714) than surgical complications (C = 0.630). CONCLUSION: Although surgical complications of hysterectomy are more common than medical complications, risk adjustment methods that use routinely collected administrative data are better at predicting medical complications. Ambiguities in coding, misclassification, and uncoded factors such as disease severity limit the utility of administrative data for risk adjustment for hysterectomy complications.
Adult↗
Sorption of copper(II) ion from aqueous solution by Tectona grandis l.f. (teak leaves powder).
Studies on a batch sorption system using Tectona grandis l.f. as adsorbent was investigated to remove copper(II) from aqueous solutions. The adsorption experiments were performed under various conditions such as different initial concentrations, pH, adsorbent dosage and adsorbent particle size. The data showed that 0.1 g of Tectona grandis l.f. was found to remove 71.66% of 20 mg/L copper(II) from 30 mL aqueous solution in 180 min. The experimental equilibrium data were adjusted by the adsorption isotherms from Langmuir and Freundlich models and their equilibrium parameters were determined. The best-adjusted model to the experimental equilibrium data for Tectona grandis l.f. was the Langmuir model. Using the Langmuir model equation, the monolayer sorption capacity of Tectona grandis l.f. was evaluated and found to be 95.40 mg/g. The optimum pH value was found to be 5.5. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. The dynamic data fitted the pseudo-second-order kinetic model.
Adsorption↗
Visit-level acuity and resource-based relative value unit utilization in a pediatric emergency department.
OBJECTIVE: There is currently limited data on the distribution of evaluation and management (E&M) codes and resource utilization in pediatric emergency departments. We sought to ascertain the following: (1) the distribution of visit-level acuity among patients who sought care in our pediatric emergency department (PED); (2) mean relative value units per physician hour (RVUs/h) as a measure of health care provider productivity; (3) the extent of correlation between the mean number of patients seen per hour and RVUs/h; and (4) the difference in RVU's generated using observation codes versus a higher level E&M code for diagnoses that require an extended level of service. DESIGN/METHODS: The study was conducted at an urban tertiary level, university-affiliated PED in a freestanding children's hospital. After obtaining data from patient encounters during the period from January through December 2004, we calculated total RVUs by using 2004 national Medicare data that pertained to facility coding, adjusted for data from Tennessee. We also reviewed the frequency of 3 diagnoses that usually require extended care to determine disposition (status asthmaticus [International Classification of Disease-9 Diagnosis Code 493.91], volume depletion [276.5], and sickle cell disease with crisis [282.62]). Utilizing a high-level E&M code (99285) and high-level, same day observation code (99236), we compared RVUs generated for each of the earlier said diagnoses. RESULTS: During the study period, 61,444 patient encounters occurred. Of the patients seen, 4678 (7.6%) were admitted. The most common E&M code used was 99283 (53.7%). The mean RVU's/h for pediatric emergency medicine physicians and for pediatricians (and nurse practitioners) were 4.36 and 3.08, respectively. There was high correlation between RVU's/h and the number of patients seen per hour (r = 0.85). The cumulative frequency of the 3 diagnoses that required extended care was 2602. Total RVUs generated when the high-level E&M code 99285 and the high-level observation code 99236 were used was 10,408 and 15,143, respectively. CONCLUSIONS: Our descriptive study provides PED benchmarking data on E&M code distribution and RVU utilization. RVU's/h may serve as a reliable measure of productivity. Although the use of observational codes in the PED requires additional documentation, their use for select diagnoses may appropriately reflect the level of service and have a favorable impact on the total number of RVU's generated.
Child↗
Effect of adjustment of maternal serum alpha-fetoprotein levels in insulin-dependent diabetes mellitus.
Our objective was to determine the effect of the 20% upward adjustment of maternal serum alphafetoprotein (MSAFP) in patients with insulin-dependent diabetes mellitus (IDDM) on the number of patients that would be classified at increased risk for pregnancy complicated by either Down syndrome (DS) or neural tube defect (NTD). We retrospectively evaluated a database containing 63,110 patients who underwent multiple serum marker screening between 14 and 22 weeks gestation; 620 patients with IDDM had measurements of MSAFP of which 479 also had measurements of beta-HCG, allowing calculation of DS risk. Increased NTD risk was defined as MSAFP >2.5 MOM while increased DS risk was defined as a calculated risk > or =1/270. One IDDM patient delivered an infant with a NTD; it was not detected on serum screening. No infants were born with DS. Of the 620 patients with MSAFP determinations, 9 had values >2.5 MOM before adjustment. After upward adjustment, 7 additional patients were identified. Sixteen patients were identified at increased risk for DS before and after adjustment. Our data suggest that the 20% upward adjustment of MSAFP increases by 78%, the number of patients who would require further evaluation for NTD's. Although we were able to identify 620 women with IDDM who underwent serum screening for NTD, the low prevalence of NTD's did not allow us to demonstrate an increased detection rate. The effect of upward adjustment of MSAFP on the number of patients categorized at increased DS risk appears to be minimal.
Adult↗
A cost-utility analysis of chronic spinal pain treatment outcomes: converting SF-36 data into quality-adjusted life years.
OBJECTIVES: The present retrospective case review study sought to analyze the cost-utility, expressed in cost/quality-adjusted life years (QALY), of current chronic spinal pain treatments. In addition, it expands upon previously published data evaluating the efficacy of interdisciplinary pain management in relation to medication management. METHODS: A recently developed algorithm was used to calculate QALYs using SF-36, v. 1 responses for 121 patients receiving treatment for chronic spinal pain at a pain rehabilitation center. Treatment groups evaluated were: (1) interdisciplinary program completers who received medication management and supplementary anesthetic procedures; (2) interdisciplinary program completers receiving medication management but not anesthetic procedures; (3) patients receiving medication management alone; and (4) patients receiving medication management with supplemental anesthetic procedures. Assessments were conducted at pretreatment and 6 months after the initiation of treatment. RESULTS: One-way analyses of covariance indicated that patients who participated in an interdisciplinary pain management program, which included medication management, psychotherapy, group education, and physical therapy, reported significantly less impairment in daily activities of living, less subjective experience of pain, and a higher quality of life and more preferred health state at the completion of their treatment phase, relative to patients receiving medication with or without anesthetic procedures. In addition, improvements in all outcome measures between pretreatment and posttreatment were significantly greater for those patients completing the interdisciplinary component of treatment. Cost-utility analyses revealed that the interdisciplinary treatment alone group was cost-saving, relative to the medication and procedures alternative, suggesting the former modality was both less costly and more effective than the latter. DISCUSSION: Average cost-utility ratios for both interdisciplinary treatment groups, ranging from 57,627 dollars /QALY to 75,885 dollars /QALY, were within established cost-effective parameters (20,000 dollars to 100,000 dollars /QALY, generally considered a good value), whereas cost-utility ratios for the standard care treatment groups were not interpretable because of a decrease in QALYs from pretreatment to posttreatment.
Adult↗
Adjusting surgical mortality rates for patient comorbidities: more harm than good?
Background. Studies of medical admissions have questioned the validity of using claims data to adjust for preexisting medical conditions (comorbidities), but the impact of using comorbidities from claims data to risk-adjust mortality rates for high-risk surgery is not well characterized. The purpose of this study was to evaluate the relationship between comorbidities and mortality in administrative data in surgical populations and identify better risk-adjustment methods. Methods. Using the national Medicare database (1994-1997), we identified admissions for elective abdominal aortic aneurysm repair (140,577) and pancreaticoduodenectomy (10,530). We calculated the relative risk of mortality (adjusted for age, sex, race, and admission acuity) for 5 chronic conditions that are known (from clinical series) to increase the risk of postoperative mortality and are commonly used in claims-based risk-adjustment models. To explore the potential value of alternative risk-adjustment strategies, we examined relationships between surgical mortality and comorbidities using diagnosis codes identified from previous admissions. Results. Overall, in-hospital mortality for elective abdominal aortic aneurysm (AAA) repair and pancreaticoduodenectomy were 5.1% and 10.4%, respectively. For both procedures, 3 of the 5 comorbidities were associated with decreased risk of mortality: prior myocardial infarction (MI) [RR = 0.38; 95% confidence interval (CI), 0.33-0.43 for AAA; RR = 0.38; 95% CI, 0.21-0.69 for pancreaticoduodenectomy), malignancy (RR = 0.67; 95% CI, 0.59-0.76 for AAA; RR = 0.74; 95% CI, 0.45-1.21 for pancreaticoduodenectomy], and diabetes (RR = 0.76; 95% CI, 0.64-0.84 for AAA; RR = 0.59; 95% CI, 0.49-0.69 for pancreaticoduodenectomy). Using comorbidities identified from prior admissions increased the mortality risk estimates for prior MI (RR = 1.22; 95% CI, 1.08-1.38 for AAA; RR = 0.80; 95% CI, 0.49-1.30 for pancreaticoduodenectomy) and diabetes (RR = 1.41; 95% CI, 1.25-1.59 for AAA; RR = 0.94; 95% CI, 0.78-1.14 for pancreaticoduodenectomy). Conclusions. Because comorbidities coded on the index admission appear protective, incorporating them in risk-adjustment models for studies comparing surgical performance may penalize providers for taking care of sicker patients. When available, comorbidity information from prior hospitalizations may be more useful for risk adjustment.
Aortic Aneurysm, Abdominal↗
Statistical methods to adjust for date and age misreporting to improve estimates of vital rates in Pakistan.
Misreporting of dates and ages poses serious difficulties for the estimation of the age distribution and birth and death rates in many developing countries. The pervasiveness of these problems is illustrated with data from a well-designed on-going survey in Pakistan, the Pakistan Demographic Survey. Methods for reconciling discrepancies, based on the assumptions of constant misreporting and survivorship patterns, are presented. The reasoning behind these methods could be applied much more generally. Research into the cultural interpretations of age and dates, and the nature of possible biases, is called for.
Birth Rate↗
Epidemiological studies of chronic disease: maladjustment of observed mortality rates.
Age adjustment of observed mortality and morbidity rates is not a substitute for age-specific analysis. Measures of association between potential causal factors and adjusted mortality rates are functions of the particular adjustment procedure and the choice of reference population. We exhibit here the wide variation in simple correlation statistics that occurs with eight adjustment methods and three reference populations. We then generalize these results to the multivariate situation showing an example in which there is coherent structure for the associations between predictors and mortality. This is contrasted with another example in which no such meaningful pattern exists. Studies are cited that could have been improved by greater attention to the underlying structure of age-adjusted rates. Age adjustment of total observed rates yields meaningless numbers that are useful for comparative purposes only. Total observed rates have substantive meaning but provide useful etiological clues primarily when supported by analyses of appropriate age-specific data.
Adolescent↗