Does clinical evidence support ICD-9-CM diagnosis coding of complications?

Evaluating diagnosis-based risk-adjustment methods in a population with spinal cord dysfunction

OBJECTIVE

To examine performance of models in predicting health care utilization for individuals with spinal cord dysfunction.

DESIGN

Regression models compared 2 diagnosis-based risk-adjustment methods, the adjusted clinical groups (ACGs) and diagnostic cost groups (DCGs). To improve prediction, we added to our model: (1) spinal cord dysfunction-specific diagnostic information, (2) limitations in self-care function, and (3) both 1 and 2.

SETTING

Models were replicated in 3 populations.

PARTICIPANTS

Samples from 3 populations: (1) 40% of veterans using Veterans Health Administration services in fiscal year 1997 (FY97) (N=1,046,803), (2) veteran sample with spinal cord dysfunction identified by codes from the International Statistical Classification of Diseases, 9th Revision, Clinical Modifications (N=7666), and (3) veteran sample identified in Veterans Affairs Spinal Cord Dysfunction Registry (N=5888).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Inpatient, outpatient, and total days of care in FY97.

RESULTS

The DCG models (R(2) range,.22-.38) performed better than ACG models (R(2) range,.04-.34) for all outcomes. Spinal cord dysfunction-specific diagnostic information improved prediction more in the ACG model than in the DCG model (R(2) range for ACG,.14-.34; R(2) range for DCG,.24-.38). Information on self-care function slightly improved performance (R(2) range increased from 0 to.04).

CONCLUSIONS

The DCG risk-adjustment models predicted health care utilization better than ACG models. ACG model prediction was improved by adding information.

Renal disease among males with haemophilia

Haematuria is common among persons with haemophilia (PWH), but its long-term effects on the kidney and renal function are not well defined. In addition, infection with human immunodeficiency virus (HIV) or hepatitis C, or exposure to nephrotoxic agents as therapy for these infections may place PWH at increased risk for renal disease. To examine factors associated with chronic renal disease (CRD) and acute renal disease (ARD) in PWH, we analysed data collected from the medical records of 3422 males with haemophilia living in six US states from 1993 to 1998. Renal disease cases were ascertained from among 2075 persons who were hospitalized at least once over the 6-year period. Of these, 60 (2.9%) were diagnosed during one or more hospitalizations with either ARD (29/60) or CRD (31/60). In multivariate analyses, we examined associations between renal disease and demographic and clinical factors including age, race, haemophilia type and severity, hypertension, diabetes, history of recent renal bleeds, presence of an inhibitor, and infection with hepatitis C or HIV. HIV infection and hypertension were strongly associated with both ARD and CRD. PWH who had ARD were also more likely to have an inhibitor than those without this diagnosis. PWH who had CRD were more likely to be older and non-white and to have had a recent admission for a kidney bleed than those without diagnosed CRD. In summary, we found that HIV infection and haemophilia-related factors including inhibitors and kidney bleeds were associated with renal disease in a cohort of males with haemophilia.

Age-dependent differences in short-term outcome after surgical or endovascular treatment of unruptured intracranial aneurysms in the United States, 1996-2000

INTRODUCTION

Unruptured intracranial aneurysm patients are frequently eligible for both open surgery ("clipping") and endovascular repair ("coiling"). We compared short-term end points (mortality, discharge disposition, complications, length of stay, and charges) for clipping and coiling in a nationally representative discharge database.

METHODS

We conducted a retrospective cohort study using Nationwide Inpatient Sample data from 1996 to 2000. Multivariate logistic regression analyses adjusted for age, sex, race, payer status, geographic region, presenting signs and symptoms, admission type and source, procedure timing, hospital caseload, and possible clustering of outcomes within hospitals. The results were confirmed by performing propensity score analysis.

RESULTS

A total of 3498 patients had clipping, and 421 underwent coiling. Clipped patients were slightly younger (P < 0.001). Medical comorbidity was similar between the groups. More clipped patients had urgent or emergency admissions (P = 0.02). More coiling procedures were performed on hospital Day 1 (P = 0.007). When only death and discharge to long-term care were counted as adverse outcomes, there was no significant difference between clipping and coiling. On the basis of a four-level discharge status outcome scale (dead, long-term care, short-term rehabilitation, or discharge to home), coiled patients had a significantly better discharge disposition (odds ratio, 2.1; P < 0.001). With regard to patient age, most of the difference in discharge disposition was in patients older than 65 years of age. The degree of difference between treatments increased from 1996 to 2000. Neurological complications were coded twice as frequently in clipped patients as in coiled patients (P = 0.002). Length of stay was longer (5 d versus 2 d, P < 0.001) and charges were higher ($21,800 versus $13,200, P = 0.007) for clipped patients than for coiled patients.

CONCLUSION

There was no significant difference in mortality rates or discharge to long-term facilities after clipping or coiling of unruptured aneurysms. When discharge to short-term rehabilitation was counted as an adverse event, coiled patients had significantly better outcomes than clipped patients at the time of hospital discharge, but most of the coiling advantage was concentrated in patients older than 65 years of age. Even in older patients, long-term end points-including long-term functional status in patients discharged to rehabilitation and efficacy in preventing hemorrhage-will be critical in determining the best treatment option for patients with unruptured aneurysms.

How safe is primary knee replacement surgery? Perioperative complication rates in Northern Illinois, 1993-1999

OBJECTIVE

To describe inpatient complications for primary total knee replacement (TKR) in a period of rapidly growing orthopedic surgery capacity, declining length of stay, and more frequent discharge to rehabilitation facilities.

METHODS

Complication incidence according to published coding algorithms was estimated for 35,531 primary TKR admissions of northern Illinois residents to 65 Illinois hospitals. Complication odds were estimated as a function of patients' clinical and sociodemographic status, hospital volume, residency training, TKR length of stay, International Classification of Diseases, Ninth Revision (ICD-9) coding intensity, and discharges to skilled nursing or rehabilitation facilities.

RESULTS

Primary TKR admissions increased 36% between 1993 and 1999, length of stay declined 43%, average ICD-9 code use increased 31%, and rehabilitation discharges increased 68%. Major complication rates declined 44% (12.4% to 6.9%; P < 0.0001) over this period, reflecting a 50% reduction in the adjusted odds of complication between 1993 and 1999. There was no association of procedure volume and outcome.

CONCLUSION

It is likely that the reduction in complications reflects true safety improvements as well as reduced length of stay.

Do Complication Screening Programs Detect Complications Present at Admission?

BACKGROUND

A study was undertaken to verify the accuracy of computer algorithms on administrative data to identify hospital complications. The assessment was based on a medical records indicator that differentiated hospital-acquired conditions from preexisting comorbidities.

METHODS

The indicators for identifying potential hospital complications were applied to all secondary diagnoses to distinguish hospital-acquired from preexisting conditions for all 1997-1998 discharges.

RESULTS

Of the 95 defined complication types, cases were found with secondary diagnoses that met the criteria for 71 different complications. Sixty-nine of these complications had one or more cases with the trigger diagnosis coded as an acquired condition. Thirty-five complications had at least 30 cases with acquired conditions. Hospital complications add greatly to costs; for example, postoperative septicemia increased the hospital bill by more $25,000, added 13 hospital days to the stay, and increased hospital mortality by 16.6%.

CONCLUSIONS

Current complication algorithms identify many cases where the condition was actually present on hospital admission. This fact, coupled with the known variability in coding between institutions, makes comparisons between hospitals on many of the complications problematic. Collection of the present-on-admission flag significantly reduces the noise in monitoring complication rates.

Administrative data based patient safety research: a critical review

Administrative data are readily available, inexpensive, computer readable, and cover large populations. Despite coding irregularities and limited clinical details, administrative data supplemented by tools such as the Agency for Healthcare Research and Quality (AHRQ) patient safety indicators (PSIs) could serve as a screen for potential patient safety problems that merit further investigation, offer valuable insights into adverse impacts and risks of medical errors and, to some extent, provide benchmarks for tracking progress in patient safety efforts at local, state, or national levels.

Quality of Evidence

BACKGROUND

In 1998, the Committee on Health Care Quality in America was created and given the charge of devising a strategy to achieve substantial improvement in the quality of health care for all Americans. One strategy to move the quality agenda forward is the use of evidence by both providers of health care and consumers of health care. One feature of this agenda, evidence-based practice, refers to a hierarchy of evidence ranging from individual randomized, controlled trials to expert opinion.

OBJECTIVES

The purposes of this article are to describe the evidence base in nursing, discuss the quality and strength of nursing's evidence, illustrate the application of the Quality Health Outcomes Model, and present recommendations for practice, research, and policy to increase nursing's contribution to quality health care.

RESULTS AND RECOMMENDATIONS

Nurses everywhere must use innovative solutions to operationalize the "evidence" in evidence-based nursing. The Quality Health Outcomes Model (QHOM) provides a useful way of advancing research and evidence about the quality of health care in America. In concert with the conceptual framework for the National Health Care Quality Report, the QHOM provides a map for identifying evidence gaps and research questions arising from the model and conceptual framework, as well as evidence synthesis (integrating methodologic quality) driven by theoretical understanding.

Postoperative mortality and pulmonary complication rankings: how well do they correlate at the hospital level?

BACKGROUND

Postoperative mortality rankings are used alone for quality assessment.

OBJECTIVES

To determine the correlation between hospital rankings of postoperative respiratory failure, pneumonia, and mortality rates and to assess the influence of hospital volume, type of surgery, and time on these correlations. To compare hospital outlier detection with and without pulmonary complication rates.

RESEARCH DESIGN

Prospective observational study.

SUBJECTS

103,176 noncardiac surgery patients from 123 VA hospitals enrolled between 1/1/94 and 8/31/95. Preoperative pneumonia, ventilator dependent, comatose, or do-not-resuscitate patients were excluded.

MEASURES

Respiratory failure was defined as greater than 48 hours of ventilator assistance or postoperative reintubation. Pneumonia was defined as positive sputum cultures with antibiotic treatment or chest x-ray infiltrate diagnosed as pneumonia or pneumonitis. Mortality was defined as death within 30 days of surgery. Hospital rankings were assigned using risk-adjusted observed-to-expected ratios.

RESULTS

There was significant, but weak correlation between mortality and pulmonary complication rankings (r = 0.21, P = 0.02 for pneumonia; r = 0.22, P = 0.01 for respiratory failure). Correlations with mortality rankings were highest for thoracic (r = 0.42, P < 0.001 for pneumonia; r = 0.38, P < 0.001 for respiratory failure) and vascular surgery (r = 0.26, P = 0.02 for pneumonia; r = 0.35, P < 0.001 for respiratory failure). Supplementing mortality with pulmonary complication outlier designations enhanced outlier detection for 47% of hospitals overall, and for 29% in the lowest caseload quartile.

CONCLUSIONS

Pulmonary complication rankings correlate weakly with mortality overall, but have higher correlations in thoracic, vascular, and upper abdominal surgery. Examining pneumonia and respiratory failure outlier status with mortality outlier status enhances hospital outlier detection even in low-volume hospitals.

Dehydration in black and white older adults using diuretics

PURPOSE

To assess the association between dehydration and ethnicity in older adults; and to determine if diuretic use can help explain the disparity between blacks and whites in diagnosis of dehydration.

METHODS

We conducted a case-control study in black and white older adults in a pharmaceutical assistance program who were hospitalized during 1997. Cases were all those diagnosed with dehydration (N=9186). Randomly selected controls were 4:1 frequency matched to cases by sex and age group (N(Total)=45585).

RESULTS

Patients taking loop, potassium-sparing, thiazide or combination diuretics were more likely to have a diagnosis of dehydration. Dehydration diagnosis was associated with being black (odds ratio (OR)=1.49, 95% confidence interval (CI), 1.36-1.63, p<.001), independent of diuretic use or dosage. That association remained when examining loop (OR=1.36, 95% CI, 1.10-1.63, p<.004) and thiazide diuretic users (OR=1.59, 95% CI, 1.09-2.34, p=.017), but not potassium-sparing or combination diuretic users.

CONCLUSION

Diuretic use is significantly associated with dehydration diagnosis, but the greater likelihood of older blacks being diagnosed with dehydration is independent of diuretic use. The increased risk of morbidity and mortality associated with dehydration suggests that further examination of the root cause of this disparity in risk is warranted.

Validity of hospital discharge International Classification of Diseases (ICD) codes for identifying patients with hyponatremia

Medical diagnosis can be studied using various sources of information, such as medical and hospital discharge records and laboratory measurements. These sources do not always concur. The objective of the present study was to assess the sensitivity, specificity, and positive and negative predictive values of hospital discharge diagnosis compared with clinical laboratory data for the identification of hyponatremia. Patients with hyponatremia were selected from a hospital information system determined by the International Classification of Diseases, 9th edition (ICD-9). The validity parameters for hyponatremia (ICD code 276.1) were estimated by comparison with accurate serum sodium (Na+) levels. A total of 2632 cases of hyponatremia were identified using laboratory measurements (Na+ < or =135 mmol/L). The sensitivity of ICD coding for hyponatremia was maximally about 30% for patients with very severe hyponatremia (Na+ < or =115 mmol/L). Corresponding specificities were high (>99%). In 87% of the cases with severe hyponatremia (Na+ < or =125 mmol/L), other discharge ICD codes reflecting severe morbidity were found. This study suggests that ICD codes for hyponatremia represent only one third of the patients admitted to the hospital and experiencing hyponatremia. About two thirds of the patients with hyponatremia were classified as hospitalized for other reasons. To assess the validity of case finding of patients with hyponatremia, the use of analytical techniques, such as certain laboratory measurements, is advisable.

In-hospital Mortality and Morbidity after Surgical Treatment of Unruptured Intracranial Aneurysms in the United States, 1996–2000: The Effect of Hospital and Surgeon Volume

OBJECTIVE

We sought to determine the risk of adverse outcome after contemporary surgical treatment of patients with unruptured intracranial aneurysms in the United States. Patient, surgeon, and hospital characteristics were tested as potential outcome predictors, with particular attention to the surgeon's and hospital's volume of care.

METHODS

We performed a retrospective cohort study with the Nationwide Inpatient Sample, 1996 to 2000. Multivariate logistic and ordinal regression analyses were performed with endpoints of mortality, discharge other than to home, length of stay, and total hospital charges.

RESULTS

We identified 3498 patients who were treated at 463 hospitals, and we identified 585 surgeons in the database. Of all patients, 2.1% died, 3.3% were discharged to skilled-nursing facilities, and 12.8% were discharged to other facilities. The analysis adjusted for age, sex, race, primary payer, four variables measuring acuity of treatment and medical comorbidity, and five variables indicating symptoms and signs. The statistics for median annual number of unruptured aneurysms treated were eight per hospital and three per surgeon. High-volume hospitals had fewer adverse outcomes than hospitals that handled comparatively fewer unruptured aneurysms: discharge other than to home occurred after 15.6% of operations at high-volume hospitals (20 or more cases/yr) compared with 23.8% at low-volume hospitals (fewer than 4 cases/yr) (P = 0.002). High surgeon volume had a similar effect (15.3 versus 20.6%, P = 0.004). Mortality was lower at high-volume hospitals (1.6 versus 2.2%) than at hospitals that handled comparatively fewer unruptured aneurysms, but not significantly so. Patients treated by high-volume surgeons had fewer postoperative neurological complications (P = 0.04). Length of stay was not related to hospital volume. Charges were slightly higher at high-volume hospitals, partly because arteriography was performed more frequently than at hospitals that handled comparatively fewer unruptured aneurysms.

CONCLUSION

For patients with unruptured aneurysms who were treated in the United States between 1996 and 2000, surgery performed at high-volume institutions or by high-volume surgeons was associated with significantly lower morbidity and modestly lower mortality.

Adherence to surveillance among patients with superficial bladder cancer

BACKGROUND

Patients diagnosed with superficial bladder cancer who have not undergone total cystectomy are at high risk for recurrence, and bladder surveillance with cystoscopy is recommended for such patients every 3-6 months. We examined the degree to which bladder cancer patients undergo the recommended surveillance procedures and identified patient and primary care provider characteristics associated with nonadherence to these recommendations.

METHODS

We used information obtained from the Surveillance, Epidemiology, and End Results (SEER) Program-Medicare-linked database to identify 6717 patients aged 65 years or older who were diagnosed with superficial bladder cancer from 1992 through 1996 and who survived for at least 3 years after diagnosis but did not have a total cystectomy. We used information obtained from Medicare claims forms to examine the frequency with which these patients had a surveillance examination of the bladder during each of five contiguous 6-month intervals from month 7 to month 36 following diagnosis. We examined characteristics of patients and their physicians that were associated with low-intensity surveillance (defined as having an examination during fewer than two of the five possible follow-up intervals). Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

Only 40% of the entire cohort had an examination during all five intervals; 1216 patients (18.1%) had low-intensity surveillance. Patient characteristics that were independently associated with low-intensity surveillance were being age 75 years or older (adjusted OR = 1.54, 95% CI = 1.35 to 1.74), nonwhite (adjusted OR = 1.94, 95% CI = 1.57 to 2.40), and having favorable tumor histology (adjusted OR = 0.59, 95% CI = 0.48 to 0.72 for poorly differentiated versus referent well-differentiated tumor grade) and high comorbidity (adjusted OR = 1.72, 95% CI = 1.30 to 2.27). Residence in an urban area or in a census tract with low median income was also associated with low-intensity surveillance.

CONCLUSIONS

The actual practice of surveillance for patients with superficial bladder cancer differs substantially from the standards recommended in clinical guidelines.

Using routine comparative data to assess the quality of health care: understanding and avoiding common pitfalls

Measuring the quality of health care has become a major concern for funders and providers of health services in recent decades. One of the ways in which quality of care is currently assessed is by taking routinely collected data and analysing them quantitatively. The use of routine data has many advantages but there are also some important pitfalls. Collating numerical data in this way means that comparisons can be made--whether over time, with benchmarks, or with other healthcare providers (at individual or institutional levels of aggregation). Inevitably, such comparisons reveal variations. The natural inclination is then to assume that such variations imply rankings: that the measures reflect quality and that variations in the measures reflect variations in quality. This paper identifies reasons why these assumptions need to be applied with care, and illustrates the pitfalls with examples from recent empirical work. It is intended to guide not only those who wish to interpret comparative quality data, but also those who wish to develop systems for such analyses themselves.

Hospital readmissions after hospital discharge for hip fracture: surgical and nonsurgical causes and effect on outcomes

OBJECTIVES

To examine the causes of hospital readmission after hip fracture and the relationships between hospital readmission and 6-month physical function and mortality.

DESIGN

Prospective, multisite, observational cohort study.

SETTING

Four hospitals in the New York City metropolitan area.

PARTICIPANTS

Five hundred sixty-two patients hospitalized for hip fracture aged 50 and older and discharged alive in 1997-1998.

MEASUREMENTS

Patient demographic characteristics, type of fracture and repair, comorbid conditions, postoperative complications, do not resuscitate status, and active clinical problems at the time of hospital discharge. Prefracture and 6-month mobility were measured using the Functional Independence Measure. Hospital readmissions and International Classification of Diseases, Ninth Revision principal diagnoses were ascertained from hospital admission/discharge databases, the New York Statewide Planning and Research Cooperative System, medical record review, and patient self-report.

RESULTS

Eighty-two percent of participants were women, and 93% were white. Within 6 months after hospital discharge, 178 (32%) patients were readmitted to the hospital, with 45 (8%) readmitted more than once. Forty-seven of 233 readmissions (20%) occurred within the first 2 weeks after discharge, and 80 (34%) occurred within 4 weeks. Over 6 months, 89% of readmissions were for nonsurgical problems, of which infectious (21%) and cardiac (12%) diseases were the most common. In multivariate analyses, patients who were readmitted were more likely to require total assistance with ambulation at 6 months (odds ratio (OR) = 2.7, 95% confidence interval (CI) = 1.6-4.6) and to die (OR = 4.0, 95% CI = 2.2-7.3) than those not readmitted.

CONCLUSION

Hospital readmissions after hip fracture are largely due to nonsurgical illness and are associated with increased morbidity and mortality.

Prognostic factors following curative resection for pancreatic adenocarcinoma: a population-based, linked database analysis of 396 patients

OBJECTIVE

To analyze prognostic factors influencing pancreatic cancer survival following curative resection, using prospectively collected, population-based data.

SUMMARY BACKGROUND DATA

Several studies have analyzed the determinants of long-term survival in postresection pancreatic cancer patients, but the majority of these have been single-institutional chart reviews yielding inconsistent results.

METHODS

This retrospective cohort study examined 396 Medicare-eligible patients over age 65 who were diagnosed with nonmetastatic pancreatic adenocarcinoma and who underwent surgical resection with curative intent while residing in one of the 11 Survival, Epidemiology, and End Results (SEER) registries between January 1991 and December 1996. Linked Medicare data provided information on treatment and comorbidity, while linked census tract data supplied sociodemographic characteristics.

RESULTS

Median survival for the overall study population was 17.6 months, with 1- and 3-year survival rates of 60.1% and 34.3%, respectively. Survival appears to be gradually improving over time, concomitant with a rise in the proportion of patients undergoing surgery in teaching centers. Prognostic variables significantly diminishing survival on univariate analysis included African American race, treatment not in a teaching hospital, lack of adjuvant chemoradiation therapy, as well as histopathologic factors that included tumor size larger than 2 cm in diameter, moderate to poor histologic grade, and positive lymph node metastases. Higher socioeconomic status was associated both with an increased likelihood of receiving adjuvant therapy and improved overall survival. Multivariate analyses indicated the strongest predictors of survival were adjuvant combined chemoradiotherapy, small tumors (<2 cm in diameter), negative lymph nodes, well-differentiated histology, undergoing surgery in a teaching hospital, and high socioeconomic status.

CONCLUSIONS

Although biologic characteristics remain important predictors of survival for patients with resected pancreatic cancer, the most powerful determinant is postoperative adjuvant chemoradiation therapy. An interesting finding that warrants further investigation is the effect of socioeconomic status on both the likelihood of receiving adjuvant treatment and subsequent survival, indicating a possible relationship between the quality of care delivered and outcomes.

Electronically screening discharge summaries for adverse medical events

OBJECTIVE

Detecting adverse events is pivotal for measuring and improving medical safety, yet current techniques discourage routine screening. The authors hypothesized that discharge summaries would include information on adverse events, and they developed and evaluated an electronic method for screening medical discharge summaries for adverse events.

DESIGN

A cohort study including 424 randomly selected admissions to the medical services of an academic medical center was conducted between January and July 2000. The authors developed a computerized screening tool that searched free-text discharge summaries for trigger words representing possible adverse events.

MEASUREMENTS

All discharge summaries with a trigger word present underwent chart review by two independent physician reviewers. The presence of adverse events was assessed using structured implicit judgment. A random sample of discharge summaries without trigger words also was reviewed.

RESULTS

Fifty-nine percent (251 of 424) of the discharge summaries contained trigger words. Based on discharge summary review, 44.8% (327 of 730) of the alerted trigger words indicated a possible adverse event. After medical record review, the tool detected 131 adverse events. The sensitivity and specificity of the screening tool were 69% and 48%, respectively. The positive predictive value of the tool was 52%.

CONCLUSION

Medical discharge summaries contain information regarding adverse events. Electronic screening of discharge summaries for adverse events using keyword searches is feasible but thus far has poor specificity. Nonetheless, computerized clinical narrative screening methods could potentially offer researchers and quality managers a means to routinely detect adverse events.

Prognostic factors following curative resection for pancreatic adenocarcinoma: a population-based, linked database analysis of 396 patients

OBJECTIVE

To analyze prognostic factors influencing pancreatic cancer survival following curative resection, using prospectively collected, population-based data.

SUMMARY BACKGROUND DATA

Several studies have analyzed the determinants of long-term survival in postresection pancreatic cancer patients, but the majority of these have been single-institutional chart reviews yielding inconsistent results.

METHODS

This retrospective cohort study examined 396 Medicare-eligible patients over age 65 who were diagnosed with nonmetastatic pancreatic adenocarcinoma and who underwent surgical resection with curative intent while residing in one of the 11 Survival, Epidemiology, and End Results (SEER) registries between January 1991 and December 1996. Linked Medicare data provided information on treatment and comorbidity, while linked census tract data supplied sociodemographic characteristics.

RESULTS

Median survival for the overall study population was 17.6 months, with 1- and 3-year survival rates of 60.1% and 34.3%, respectively. Survival appears to be gradually improving over time, concomitant with a rise in the proportion of patients undergoing surgery in teaching centers. Prognostic variables significantly diminishing survival on univariate analysis included African American race, treatment not in a teaching hospital, lack of adjuvant chemoradiation therapy, as well as histopathologic factors that included tumor size larger than 2 cm in diameter, moderate to poor histologic grade, and positive lymph node metastases. Higher socioeconomic status was associated both with an increased likelihood of receiving adjuvant therapy and improved overall survival. Multivariate analyses indicated the strongest predictors of survival were adjuvant combined chemoradiotherapy, small tumors (<2 cm in diameter), negative lymph nodes, well-differentiated histology, undergoing surgery in a teaching hospital, and high socioeconomic status.

CONCLUSIONS

Although biologic characteristics remain important predictors of survival for patients with resected pancreatic cancer, the most powerful determinant is postoperative adjuvant chemoradiation therapy. An interesting finding that warrants further investigation is the effect of socioeconomic status on both the likelihood of receiving adjuvant treatment and subsequent survival, indicating a possible relationship between the quality of care delivered and outcomes.

Licensed nurse staffing and adverse events in hospitals

OBJECTIVE

To examine the changes in licensed nursing staff in Pennsylvania hospitals from 1991 to 1997, and to assess the relationship of licensed nursing staff with patient adverse events in hospitals.

DATA SOURCE

A convenience sample of all Pennsylvania, acute-care, hospitals, 1991 to 1997.

STUDY DESIGN

The study first describes the percentage change of licensed nursing staff categories in Pennsylvania hospitals from 1991 to 1997. Second, random effects Poisson regressions are used to assess the association of the numbers and proportions of licensed nurses with yearly iatrogenic lung collapse, pressure sores, falls, pneumonia, posttreatment infections, and urinary tract infections. Controls are the yearly number of patients, hospital acuity, and other hospital characteristics.

DATA COLLECTION

Secondary data containing patient- and hospital-level measures from three sources were recoded to establish the incidence of adverse events, aggregated to the hospital level, and merged to form one data set. PRINCIPAL FUNDING: Licensed nurses' acuity-adjusted patient load increased from 1991 to 1997. Licensed nurse/total nursing staff declined from 1994 to 1997. Greater incidence of nearly all adverse events occurred in hospitals with fewer licensed nurses. Greater incidence of decubitus ulcers and pneumonia occurred in hospitals with a lower proportion of licensed nurses.

CONCLUSIONS

This study suggests that licensed nurses' patient load began increasing in the 1990s. Adequate licensed nurse staffing is important in minimizing the incidence of adverse events in hospitals. Ensuring adequate licensed nurse staffing should be an area of major concern to hospital management. Improved measures of nurse staffing and patient outcomes, and further studies are suggested.

Can administrative data be used to compare postoperative complication rates across hospitals?

BACKGROUND

Several quality assessment systems use administrative data to identify postoperative complications, with uncertain validity.

OBJECTIVES

To determine how accurately postoperative complications are reported in administrative data, whether accuracy varies systematically across hospitals, and whether serious complications are more consistently reported.

DESIGN

Retrospective cohort.

SUBJECTS

Nine hundred ninety-one randomly sampled adults who underwent elective lumbar diskectomies at 30 nonfederal acute care hospitals in California in 1990 to 1991. Hospitals with especially low or high risk-adjusted complication rates, and patients who experienced complications, were over sampled.

MEASURES

Postoperative complications were specified by reviewing medical literature and consulting clinical experts; each complication was mapped to ICD-9-CM. Hospital-reported complications were compared with our independent recoding of the same records.

RESULTS

The weighted sensitivity, specificity, and positive and negative predictive values for reported complications were 35%, 98%, 82%, and 84%, respectively. The weighted sensitivity was 30% for serious, 40% for minor, and 10% for questionable complications. It varied from 21% among hospitals with fewer complications than expected to 45% among hospitals with more complications than expected. Only reoperation, bacteremia/sepsis, postoperative infection, and deep vein thrombosis were reported with at least 60% sensitivity. Half of the difference in risk-adjusted complication rates between low and high outlier hospitals was attributable to reporting variation.

CONCLUSIONS

ICD-9-CM complications were underreported among diskectomy patients, especially at hospitals with low risk-adjusted complication rates. The validity of using coded complications to compare provider performance is questionable, even with careful efforts to identify serious events, although these results must be confirmed using more recent data.

Trends in adverse events in hospitalized patients

The Institute of Medicine reported unacceptably high rates of medical error but did not identify whether this is a growing or a stabilized problem. This study used longitudinal data from all acute care hospitals in Pennsylvania to track rates of acuity-adjusted iatrogenic atelectasis, cardiac complications, complications in general, decubitus ulcers, gangrenous ulcers, falls, hemorrhage, mortality, penumonia, post-procedural infections, treatment complications, and urinary tract infections, from 1994 to 1997. More than one-half of these adverse events increased during this time. It is important to identify the causes and correct trends in hospital systems that may produce an increase in preventable adverse events.

Measuring complications of cancer treatment using the SEER-Medicare data

BACKGROUND

The linkage of SEER registry data with Medicare claims allows the longitudinal tracking of health care and outcomes for patients after a cancer diagnosis. One category of outcomes amenable to research using Medicare claims is complications of cancer treatments: the unintentional, adverse side effects or sequelae of interventions used to treat or palliate cancer patients.

RESEARCH DESIGN

The authors review some of the methods and limitations of using Medicare claims to identify both acute and chronic complications of cancer treatments, and present an original analysis comparing survey-based and claims-based complications following radical prostatectomy for prostate cancer to illustrate some of the potential limitations inherent in using claims for this purpose.

RESULTS

Utility of the Medicare claims for identifying postdischarge complications varies by the patient type, the initial treatment used, and any subsequent treatment of complications. For patients undergoing surgical interventions, Medicare claims can be used to identify most acute inpatient complications. However, claims data cannot be used as effectively in the long-term to capture chronic complications, particularly when the complication does not consistently prompt an intervention.

CONCLUSION

Researchers who use the SEER-Medicare-linked database to assess long-term complications of cancer treatments should exercise caution when designing and interpreting studies. Ideally, for studies of most chronic complications of cancer care, validation studies similar to the one performed here would provide valuable additional evidence to assess the credibility of conclusions based on claims data.

Validity of information on comorbidity derived rom ICD-9-CCM administrative data

BACKGROUND

The comorbidity variables that constitute the Charlson index are widely used in health care research using administrative data. However, little is known about the validity of administrative data in these comorbidities. The agreement between administrative hospital discharge data and chart data for the recording of information on comorbidity was evaluated. The predictive ability of comorbidity information in the two data sets for predicting in-hospital mortality was also compared.

METHODS

One thousand two hundred administrative hospital discharge records were randomly selected in the region of Calgary, Alberta, Canada in 1996 and used a published coding algorithm to define the 17 comorbidities that constitute the Charlson index. Corresponding patient charts for the selected records were reviewed as the "criterion standard" against which validity of the administrative data were judged.

RESULTS

Compared with the chart data, administrative data had a lower prevalence in 10 comorbidities, a higher prevalence in 3 and a similar prevalence in 4. The kappa values ranged from a high of 0.87 to a low of 0.34; agreement was therefore near perfect for one variable, substantial for six, moderate for nine, and only fair for one variable. For the Charlson index score ranging from 0 to 5 to 6 or higher, agreement was moderate to substantial (kappa = 0.56, weighted kappa = 0.71). When 16 Charlson comorbidities from administrative data were used to predict in-hospital mortality, 10 comorbidities and the index scores defined using administrative data yielded odds ratios that were similar to those derived from chart data. The remaining six comorbidities yielded odds ratios that were quite different from those derived from chart data.

CONCLUSIONS

Administrative data generally agree with patient chart data for recording of comorbidities although comorbidities tend to be under-reported in administrative data. The ability to predict in-hospital mortality is less reliable for some of the individual comorbidities than it is for the summarized Charlson index scores in administrative data.

Can administrative data be used to ascertain clinically significant postoperative complications?

The purpose of this study is to assess whether postoperative complications can be ascertained using administrative data. We randomly sampled 991 adults who underwent elective open diskectomies at 30 nonfederal acute care hospitals in California. Postoperative complications were specified by reviewing medical literature and by consulting clinical experts. We compared hospital-reported ICD-9-CM data and independently recoded ICD-9-CM data with complications abstracted by clinicians using detailed criteria. Recoded ICD-9-CM data were more likely than hospital-reported ICD-9-CM data to capture true complications, when they occurred, but they also mislabeled more patients who never experienced clinically significant complications. This finding was most evident for mild or ambiguous complications, such as atelectasis, posthemorrhagic anemia, and hypotension. Overall, recoded ICD-9-CM data captured 47% and 56% of all mild and severe complications, respectively, whereas hospital-reported ICD-9-CM data captured only 37% and 44%, respectively, of all mild and severe complications. These findings raise questions about the validity of using administrative data to ascertain postoperative complications, even if coders are carefully hired, trained, and supervised. ICD-9-CM complication codes are more promising as a tool to help providers identify their own adverse outcomes than as a tool for comparing performance.

Nurse staffing and postsurgical adverse events: an analysis of administrative data from a sample of U.S. hospitals, 1990-1996

OBJECTIVE

To examine the impact of nurse staffing on selected adverse events hypothesized to be sensitive to nursing care between 1990 and 1996, after controlling for hospital characteristics.

DATA SOURCES/STUDY SETTING

The yearly cross-sectional samples of hospital discharges for states participating in the National Inpatient Sample (NIS) from 1990-1996 were combined to form the analytic sample. Six states were included for 1990-1992, four states were added for the period 1993-1994, and three additional states were added in 1995-1996.

STUDY DESIGN

The study design was cross-sectional descriptive.

DATA COLLECTION/EXTRACTION METHODS

Data for patients aged 18 years and older who were discharged between 1990 and 1996 were used to create hospital-level adverse event indicators. Hospital-level adverse event data were defined by quality indicators developed by the Health Care Utilization Project (HCUP). These data were matched to American Hospital Association (AHA) data on community hospital characteristics, including registered nurse (RN) and licensed practical/vocational nurse (LPN) staffing hours, to examine the relationship between nurse staffing and four postsurgical adverse events: venous thrombosis/pulmonary embolism, pulmonary compromise after surgery, urinary tract infection, and pneumonia. Multivariate modeling using Poisson regression techniques was used.

PRINCIPAL FINDINGS

An inverse relationship was found between RN hours per adjusted inpatient day and pneumonia (p < .05) for routine and emergency patient admissions.

CONCLUSIONS

The inverse relationship between pneumonia and nurse staffing are consistent with previous findings in the literature. The results provide additional evidence for health policy makers to consider when making decisions about required staffing levels to minimize adverse events.

Using administrative data to study persons with disabilities

Administrative data result from administering health plans--tracking service utilization, paying claims, monitoring costs and quality--and have been used extensively for health services research. This article examines the strengths and limitations of administrative data for health services research studies of people with disabilities. Administrative data offer important advantages: encompassing large populations over time, ready availability, low cost, and computer readability. Questions arise about how to identify people with disabilities, capture disability-related services, and determine meaningful health care outcomes. Potentially useful administrative data elements include eligibility for Medicare or Medicaid through Social Security disability determinations, diagnosis and procedure codes, pharmacy claims, and durable medical equipment claims. Linking administrative data to survey or other data sources enhances the utility of administrative data for disability studies.

Rate of and risk factors for acute inpatient mortality after orthopaedic surgery

BACKGROUND

Orthopaedic surgeons operate on a diverse group of patients, and many of these patients have concomitant medical problems. The purpose of this study was to identify the rate of mortality and to evaluate the risk factors associated with mortality after orthopaedic surgery.

METHODS

Data from the National Hospital Discharge Survey, a nationwide sample of hospital admissions, were obtained for the years 1995 through 1997. The study was limited to hospital admissions. Univariate and multivariate analyses were performed.

RESULTS

The 43,215 inpatient orthopaedic operations that we evaluated were associated with a mortality rate of 0.92%. Seventy-seven percent of all deaths occurred after procedures performed for patients who were more than seventy years old, and 50% of all deaths occurred after operations performed for the treatment of hip fractures. The independent preoperative medical risk factors for death included chronic renal failure, congestive heart failure, metastasis to bone, atrial fibrillation, chronic obstructive pulmonary disease, and osteomyelitis. The risk factors of diabetes, coronary artery disease, peripheral vascular disease, septic arthritis, and rheumatoid arthritis did not achieve significance. Among orthopaedic subspecialty categories, operations for tumors, trauma, and infection were associated with elevated mortality rates. In a predictive model, five critical risk factors were identified as most helpful in identifying patients at risk for death: chronic renal failure, congestive heart failure, chronic obstructive pulmonary disease, hip fracture, and an age of greater than seventy years. The mortality rate was 0.25% for patients with no critical risk factors. A linear increase in mortality was seen with increasing numbers of critical risk factors (p < 0.005).

CONCLUSION

Death is rare after orthopaedic operations. In the United States, the rate of acute mortality after inpatient orthopaedic surgical procedures is approximately 1% for all patients, 3.1% for patients with a hip fracture, and 0.5% for patients without a hip fracture. These data will aid orthopaedic surgeons in predicting operative mortality for their patients.

Pitfalls in assessing the quality of care for patients with cardiovascular disease

PURPOSE

There are no clinical performance measures for cardiovascular diseases that span the continuum of hospital through postdischarge ambulatory care. We tested the feasibility of developing and implementing such measures for patients with acute myocardial infarction, congestive heart failure, or hypertension.

SUBJECTS AND METHODS

After reviewing practice guidelines and the medical literature, we developed potential measures related to therapy, diagnostic evaluation, and communication. We tested the feasibility of implementing the selected measures for 518 patients with myocardial infarction, 396 with heart failure, and 601 with hypertension who were enrolled in four major U.S. managed care plans at six geographic sites, using data from administrative claims, medical records, and patient surveys.

RESULTS

Difficulties in obtaining timely data and small numbers of cases adversely affected measurement. We encountered 6- to 12-month delays, disagreement between principal discharge diagnosis as coded in administrative and records data (for 9% of myocardial infarction and 21% of heart failure patients), missing medical records (20% for both myocardial infarction and heart failure patients), and problems in identifying physicians accountable for care. Low rates of performing key diagnostic tests (e.g., ejection fraction) excluded many cases from measures of appropriate therapy that were conditional on test results. Patient survey response rates were low.

CONCLUSIONS

Constructing meaningful clinical performance measures is straightforward, but implementing them on a large scale will require improved data systems. Lack of standardized data captured at the point of clinical care and low rates of eligibility for key measures hamper measurement of quality of care.

Age and adjuvant chemotherapy use after surgery for stage III colon cancer

BACKGROUND

Randomized trials have established that 5-fluorouracil-based adjuvant chemotherapy following resection of stage III colon cancer reduces subsequent mortality by as much as 30%. However, the extent to which adjuvant therapy is used outside the clinical trial setting, particularly among the elderly, is unknown.

METHODS

A retrospective cohort study utilizing the Surveillance, Epidemiology, and End Results/Medicare-linked database identified 6262 patients aged 65 years and older with resected stage III colon cancer. The primary outcome was chemotherapy use within 3 months of surgery, as ascertained from Medicare claims. We examined the extent to which age at diagnosis was associated with adjuvant chemotherapy usage, and we adjusted for potential confounding based on differences in other patient characteristics with the use of multiple logistic regression. All P values were two-sided.

RESULTS

Age at diagnosis was the strongest determinant of chemotherapy: 78% of patients aged 65-69 years, 74% of those aged 70-74 years, 58% of those aged 75-79 years, 34% of those aged 80-84 years, and 11% of those aged 85-89 years received postoperative chemotherapy. The age trend remained pronounced after adjustment for potential confounding based on variation in patients' demographic and clinical characteristics and after exclusion of patients with any evident comorbidity (all P values <.001).

CONCLUSIONS

Adjuvant chemotherapy for stage III colon cancer is used extensively, especially for patients under the age of 75 years. However, treatment rates decline dramatically with chronologic age. Because patients in their 70s and even 80s have a reasonable life expectancy, further efforts are needed to ensure that elderly patients have the opportunity to make informed decisions regarding this potentially curative treatment.