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

Sensitivity of International Classification of Diseases codes for hyponatremia among commercially insured outpatients in the United States

Background

Administrative claims are a rich source of information for epidemiological and health services research; however, the ability to accurately capture specific diseases or complications using claims data has been debated. In this study, the authors examined the validity of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes for the identification of hyponatremia in an outpatient managed care population.

Methods

We analyzed outpatient laboratory and professional claims for patients aged 18 years and older in the National Managed Care Benchmark Database from Integrated Healthcare Information Services. We obtained all claims for outpatient serum sodium laboratory tests performed in 2004 and 2005, and all outpatient professional claims with a primary or secondary ICD-9-CM diagnosis code of hyponatremia (276.1).

Results

A total of 40,668 outpatient serum sodium laboratory results were identified as hyponatremic (serum sodium < 136 mmol/L). The sensitivity of ICD-9-CM codes for hyponatremia in outpatient professional claims within 15 days before or after the laboratory date was 3.5%. Even for severe cases (serum sodium ≤ 125 mmol/L), sensitivity was < 30%. Specificity was > 99% for all cutoff points.

Conclusion

ICD-9-CM codes in administrative data are insufficient to identify hyponatremia in an outpatient population.

Regional and national health care data repositories

Efforts are underway to define a national framework for secondary analysis of health-related data. In the meantime, regional health databases have been constructed using insurance claims data, clinical data from single large health care providers, clinical data from multiple collaborating health care providers, and public health data. Large-scale survey data also are available in government databases. Clinical laboratory results are an important component of all these databases because they can provide validation for manually assigned diagnostic and procedure codes and can support inference of key information not provided by coding, such as severity of disease and prevalence of risk factors.

Hospital care for children with hydrocephalus in the United States: utilization, charges, comorbidities, and deaths

OBJECT

The aims of this study were to measure inpatient health care for pediatric hydrocephalus in the US; describe patient, hospital, and hospitalization characteristics for pediatric hydrocephalus inpatient care; and determine characteristics associated with death.

METHODS

A cross-sectional study was performed using the 1997, 2000, and 2003 Healthcare Cost and Utilization Project Kids' Inpatient Databases (KID), nationally representative weighted data sets of hospital discharges for pediatric patients. A hydrocephalus-related hospitalization was classified as either cerebrospinal fluid (CSF) shunt-related (including initial placements, infections, malfunctions, or other) or non-CSF shunt-related. Patients>18 years of age were excluded. The KID provided weighted estimates of 6.657, 6.597, and 6.732 million total discharges in the 3 study years.

RESULTS

Each year there were 38,200-39,900 admissions, 391,000-433,000 hospital days, and total hospital charges of $1.4-2.0 billion for pediatric hydrocephalus. Hydrocephalus accounted for 0.6% of all pediatric hospital admissions in the US in 2003, but for 1.8% of all pediatric hospital days and 3.1% of all pediatric hospital charges. Over the study years, children admitted with hydrocephalus were older, had an increase in comorbidities, and were admitted more frequently to teaching hospitals. Compared with children who survived, those who died were more likely to be <3 months of age and have a birth-related admission, have no insurance, have comorbidities, be transferred, and have a non-CSF shunt-related admission.

CONCLUSIONS

Children with hydrocephalus have a chronic illness and use a disproportionate share of hospital days and healthcare dollars in the US. Since 1997 they have increased in age and in number of comorbid conditions. For important changes in morbidity and mortality rates to be made, focused research efforts and funding are necessary.

Searching for a needle in a haystack: use of ICD-9-CM codes in drug-induced liver injury

OBJECTIVES

The aim of our study was to compare three search strategies using a computerized administrative database to identify cases of idiosyncratic drug-induced liver injury (DILI) due to amoxicillin/clavulanic acid, phenytoin, valproic acid, and isoniazid.

METHODS

In search 1, electronic medical records from patients seen between 1994 and 2004 with an ICD-9-CM code of acute liver injury were identified and cross-searched for the specific drug names in the dictation text. In search 2, all patients with an ICD-9-CM code of drug poisoning/overdose due to one of the four study drugs were identified. In search 3, patients with a poisoning code as well as an acute liver injury code were identified.

RESULTS

Review of the records from the 7,395 search 1 patients yielded 51 DILI cases (0.7%). In contrast, the 566 search 2 patients yielded only three DILI cases (0.5%). Finally, search 3 provided the greatest specificity but a low rate of detection with only two patients (3.9%) having DILI due to one of the four drugs.

CONCLUSION

Acute liver injury ICD-9-CM codes combined with a text search of the dictated medical record yielded the greatest number of DILI cases but was less specific than crossing acute liver injury and poisoning codes. Use of ICD-9-CM codes to identify rare adverse events like DILI remains problematic and highlights the need for prospective surveillance networks.

Comparison of mortality risk adjustment using a clinical data algorithm (American College of Surgeons National Surgical Quality Improvement Program) and an administrative data algorithm (Solucient) at the case level within a single institution

BACKGROUND

There is great interest in efficiently evaluating health care quality, but there is controversy over the use of administrative versus clinical data methods. We sought to compare actual mortality with risk-adjusted expected mortality in a sample population calculated by two different methods; one based on preexisting administrative records and one based on chart reviews.

STUDY DESIGN

We examined a sample of patients (n = 1,234) undergoing surgical procedures at an academic teaching hospital during 1 year. The first risk-adjustment method was that used by the National Surgical Quality Improvement Program, which is based on dedicated medical record review. The second method was that used by Solucient, LLC, which is based on preexisting administrative records.

RESULTS

The ratio of observed to expected mortality for this population set was higher using the National Surgical Quality Improvement Program algorithm (1.1; 95% CI, 0.8 to 1.5) than using the Solucient algorithm (0.9; 95% CI, 0.6 to 1.2) but neither estimate was notably different from 1.0. Similarly, when observed to expected mortality ratios were calculated separately for each quartile of mortality, there were no marked differences within quartiles, although minor differences with potential importance were noted. Fit was comparable by age categories, gender, and American Society of Anesthesiologists' categories. A number of actual deaths had higher predicted mortality scores using the Solucient algorithm.

CONCLUSIONS

Risk-adjusted mortality estimates were comparable using administrative or clinical data. Minor performance differences might still have implications. Because of the potential lower cost of using administrative data, this type of algorithm can be an efficient alternative and should continue to be investigated.

Tethered cord syndrome: nationwide inpatient complications and outcomes

Object

Previous investigations of health outcome after spinal surgery for tethered cord syndrome (TCS) have been single-institution studies. The aim of this study was to report inpatient complications and outcomes on a nationwide level.

Methods

The Nationwide Inpatient Sample (NIS) was used to identify patients who underwent spinal surgery for TCS in the US between 1993 and 2002. Patients who had a primary diagnosis of TCS (ICD-9 742.59) and also underwent spinal laminectomies were included in this study. Multivariate analysis was performed to analyze the effects of patient and hospital characteristics on variables such as mortality rate, nonfatal complications, LOS, and adverse outcomes in general (defined as death or discharge to an institution rather than home).

Results

The NIS sample included data on 9733 patients with TCS who underwent surgery. The means for mortality rate, complication rate, and LOS, respectively, were 0.0005%, 9.48%, and 5.6 days. Postoperative hemorrhages or hematomas (mean rate 2.3%) were the most common complications reported. Age and complications were the only significant predictors of adverse outcome on multivariate analysis. Patients older than 65 years had a threefold increase in risk of adverse outcome compared with patients 18 to 44 years of age. On average, one postoperative complication led to a 3-day increase in mean LOS and added more than $9000 to hospital charges.

Conclusions

This study provides a national perspective on inpatient complications and outcomes after spinal surgery for TCS in the United States. The authors have demonstrated the impact of age, complications, and medical comorbidities on the outcome of surgery for patients with this common disorder.

Impact of Diagnosis-Timing Indicators on Measures of Safety, Comorbidity, and Case Mix Groupings From Administrative Data Sources

CONTEXT

Many attempts to identify hospital complications rely on secondary diagnoses from billing data. To be meaningful, diagnosis codes must distinguish between diagnoses after admission and those existing before admission.

OBJECTIVE

To assess the influence of diagnoses at admission on patient safety, comorbidity, severity measures, and case mix groupings for Medicare reimbursement.

DESIGN

Cross-sectional association of various diagnosis-based clinical and performance measures with and without diagnosis present on admission.

SETTING

Hospital discharges from Mayo Clinic Rochester hospitals in 2005 (N = 60,599).

PATIENTS

All hospital inpatients including surgical, medical, pediatric, maternity, psychiatric, and rehabilitation patients. About 33% of patients traveled more than 120 miles for care.

MAIN OUTCOME MEASURES

Hospital patient safety indicators, comorbidity, severity, and case mix measures with and without diagnoses present at admission.

RESULTS

Over 90% of all diagnoses were present at admission whereas 27.1% of all inpatients had a secondary diagnosis coded in-hospital. About one-third of discharges with a safety indicator were flagged because of a diagnosis already present at admission, more likely among referral patients. In contrast, 87% of postoperative hemorrhage, 22% of postoperative hip fractures, and 54% of foreign bodies left in wounds were coded as in-hospital conditions. Severity changes during hospitalization were observed in less than 8% of discharges. Slightly over 3% of discharges were assigned to higher weight diagnosis-related groups based on an in-hospital complication.

CONCLUSIONS

In general, many patient safety indicators do not reliably identify adverse hospital events, especially when applied to academic referral centers. Except as noted, conditions recorded after admission have minimal impact on comorbidity and severity measures or on Medicare reimbursement.

Failure to rescue: validation of an algorithm using administrative data

BACKGROUND

Failure to rescue (FTR), the rate of death in patients suffering 1 of 6 in-hospital complications, is an Agency for Healthcare Research and Quality (AHRQ) Patient Safety Indicator calculated from administrative data.

OBJECTIVE

: We sought to assess the accuracy of the AHRQ FTR algorithm.

METHODS

We undertook a retrospective chart review of 60 denominator cases of FTR identified by the algorithm at each of 40 University HealthSystem Consortium institutions. The primary outcome was the overall accuracy of the algorithm compared with chart review. We also assessed accuracy by complication type, patient characteristics, institution, service assignment, and mortality.

RESULTS

Of 2354 cases, 1193 (50.7%) were accurately identified by the algorithm as having had at least one of the FTR-qualifying complications during hospitalization. Of the 3073 complications identified in these patients, 1497 (48.7%) were correctly flagged by the algorithm, 907 (29.5%) were present on admission, 419 (13.6%) were not confirmed by chart review, and 250 (8.1%) met a predefined complication-specific criterion for exclusion. The case accuracy rate varied significantly by institution (mean, 50.7%; range, 18.3-100%; P < 0.001), service assignment (surgical service, 62.9% vs. nonsurgical service, 42.9%; P < 0.001), and mortality (alive, 43.9% vs. dead, 67.5%; P < 0.001) but was not affected by patients' age, gender, race, or insurance status.

CONCLUSIONS

As currently calculated from administrative data, the FTR algorithm misidentifies half of the cases on average, is least accurate for nonsurgical cases, and is widely variable across institutions. This indicator may be useful internally to flag possible cases of quality failure but has limitations for external institutional comparisons. Improvements in coding quality and consistency across institutions are needed.

Mandatory public reporting in the USA: an example to follow?

Increasingly states in the USA are enacting laws mandating reporting and disclosure of hospital-acquired infections (HAIs). The rapid development of legislation has occurred in response to increased coverage of HAIs in the mainstream media coupled with active involvement of consumer advocacy organizations. The transformation of healthcare in the USA into a commodity has fostered a strong role for consumer advocacy to which state legislative bodies have shown willingness to respond.

The Validity of ICD-9-CM Codes in Identifying Postoperative Deep Vein Thrombosis and Pulmonary Embolism

BACKGROUND

Deep vein thrombosis and pulmonary embolism (DVT/PE) are common complications after surgery and are associated with substantial excess mortality and length of stay. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes recorded in hospital claims have been used to identify and study DVT/PE, but the validity of this method is not well studied.

METHODS

Identification of postoperative DVT/PE events were compared using ICD-9-CM codes and medical record abstraction in random samples of hospital discharges of Medicare beneficiaries in 2002-2004.

RESULTS

Among 20,868 eligible surgical hospitalizations, 232 DVT cases and 95 PE cases were identified by ICD-9-CM codes; 108 DVT cases and 31 PE cases by medical record abstraction; 72 DVT cases and 23 PE cases by both methods. The resulting estimates of PPV of ICD9-CM coding were 31% (72/232 cases) for DVT, 24% (23/95) for PE, and 29% (90/308) for DVT/PE combined. The resulting sensitivity estimates were 67% (72/108 cases) for DVT, 74% (23/31) for PE, and 68% (90/133) for DVT/PE combined.

DISCUSSION

ICD-9-CM codes in Medicare claims are sensitive but have limited predictive validity in identifying postoperative DVT/PE. Improvements in the validity are needed before the indicator can be used for safety performance assessment.

Anal Sphincter Laceration at Vaginal Delivery

OBJECTIVE

To determine the error rate for discharge coding of anal sphincter laceration at vaginal delivery in a cohort of primiparous women.

METHODS

As part of the Childbirth and Pelvic Symptoms study performed by the National Institutes of Health Pelvic Floor Disorders Network, we assessed the relationship between perineal lacerations and corresponding discharge codes in three groups of primiparous women: 393 women with anal sphincter laceration after vaginal delivery, 383 without anal sphincter laceration after vaginal delivery, and 107 after cesarean delivery before labor. Discharge codes for perineal lacerations were compared with data abstracted directly from the medical record shortly after delivery. Patterns of coding and coding error rates were described.

RESULTS

The coding error rate varied by delivery group. Of 393 women with clinically recognized and repaired anal sphincter lacerations by medical record documentation, 92 (23.4%) were coded incorrectly (four as first- or second-degree perineal laceration and 88 with no code for perineal diagnosis or procedure). One (0.3%) of the 383 women who delivered vaginally without clinically reported anal sphincter laceration was coded with a sphincter tear. No women in the cesarean delivery group had a perineal laceration diagnostic code. Coding errors were not related to the number of deliveries at each clinical site.

CONCLUSION

Discharge coding errors are common after delivery-associated anal sphincter laceration, with omitted codes representing the largest source of errors. Before diagnostic coding can be used as a quality measure of obstetric care, the clinical events of interest must be appropriately defined and accurately coded.

Health state information derived from secondary databases is affected by multiple sources of bias

OBJECTIVE

Secondary databases are used in descriptive studies of patient subgroups; evaluation of associations between individual characteristics and diagnosis, prognosis, and/or service utilization rates; and studies of the quality of health care delivered. This article identifies sources of bias for health state characteristics stored in secondary databases that arise from patients' encounters with health systems, highlighting sources of bias that arise from organizational and environmental factors.

STUDY DESIGN AND SETTING

Potential sources of bias, from patient access of services and diagnosis, through encoding and filing of patient information in secondary databases, are discussed. A patient presenting with acute myocardial infarction is used as an illustrative example.

RESULTS

The accuracy of health state characteristics derived from secondary databases is a function of both the quality and quantity of information collected before data entry and is dependent on complex interactions between patients, clinicians, and the structures and systems surrounding them.

CONCLUSION

The use of health state information included in secondary databases requires that estimates of potential bias from all sources be included in the analysis and presentation of results. By making this common practice in the field, greater value can be achieved from secondary database analyses.

Factors influencing the volume-outcome relationship in gastrectomies: a population-based study

BACKGROUND

A relationship between hospital procedural volume and patient outcomes has been observed in gastrectomies for primary gastric cancer, but modifiable factors influencing this relationship are not well elaborated.

METHODS

We performed a population-based study of 1864 patients undergoing gastrectomy for primary gastric cancers at 214 hospitals. Hospitals were stratified as high-, intermediate-, or low-volume centers. Multivariate models were constructed to evaluate the effect of institutional procedural volume and other hospital- and patient-specific factors on the risk of in-hospital mortality, adverse events, and failure to rescue, defined as mortality after an adverse event.

RESULTS

High-volume centers attained an in-hospital mortality rate of 1.0% and failure-to-rescue rate of .7%, both less than one-fifth of that seen at intermediate- and low-volume centers, although adverse event rates were similar across the three volume tiers. In multivariate modeling, treatment at a high-volume hospital decreased the odds of mortality (odds ratio [OR], .22; 95% confidence interval [95% CI], .05-.89), whereas treatment at an institution with a high ratio of licensed vocational nurses per bed increased the odds of mortality (OR, 1.96; 95% CI, 1.04-3.75). Being treated at a hospital with a greater than median number of critical care beds decreased odds of mortality (OR, .46; 95% CI, .25-.81) and failure to rescue (OR, .53; 95% CI, .29-.97).

CONCLUSIONS

Undergoing gastrectomy at a high-volume center is associated with lower in-hospital mortality. However, improving the rates of mortality after adverse events and reevaluating nurse staffing ratios may provide avenues by which lower-volume centers can improve mortality rates.

Comparison of Clinical and Administrative Data Sources for Hospital Coronary Artery Bypass Graft Surgery Report Cards

Background— Regardless of statistical methodology, public performance report cards must use the highest-quality validated data, preferably from a prospectively maintained clinical database. Using logistic regression and hierarchical models, we compared hospital cardiac surgery profiling results based on clinical data with those derived from contemporaneous administrative data.

Methods and Results— Fiscal year 2003 isolated coronary artery bypass grafting surgery results based on an audited and validated Massachusetts clinical registry were compared with those derived from a contemporaneous state administrative database, the latter using the inclusion/exclusion criteria and risk model of the Agency for Healthcare Research and Quality. There was a 27.4% disparity in isolated coronary artery bypass grafting surgery volume (4440 clinical, 5657 administrative), a 0.83% difference in observed in-hospital mortality (2.05% versus 2.88%), corresponding differences in risk-adjusted mortality calculated by various statistical methodologies, and 1 hospital classified as an outlier only with the administrative data–based approach. The discrepancies in volumes and risk-adjusted mortality were most notable for higher-volume programs that presumably perform a higher proportion of combined procedures that were misclassified as isolated coronary artery bypass grafting surgery in the administrative cohort. Subsequent analyses of a patient cohort common to both databases revealed the smoothing effect of hierarchical models, a 9% relative difference in mortality (2.21% versus 2.03%) resulting from nonstandardized mortality end points, and 1 hospital classified as an outlier using logistic regression but not using hierarchical regression.

Conclusions— Cardiac surgery report cards using administrative data are problematic compared with those derived from audited and validated clinical data, primarily because of case misclassification and nonstandardized end points.

Influence of Post-Cystectomy Complications on Cost and Subsequent Outcome

PURPOSE

Of commonly performed urological cancer procedures radical cystectomy is associated with the highest morbidity and mortality. The impact of each individual type of complication or a combination of them on various outcome measures, such as mortality, charges and length of stay, is unclear. We quantified the impact of specific post-cystectomy complications and combinations thereof in terms of mortality, charges and length of stay.

MATERIALS AND METHODS

All 6,577 patients undergoing radical cystectomy for bladder cancer were identified from the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project (1998 to 2002). The prevalence of different International Classification of Diseases, 9th Revision, Clinical Modification coded complications following cystectomy were determined. Outcome variables of interest were in-hospital mortality, total charges and length of stay. The association between types of complications and measured outcomes were examined using univariate and multivariate regression models. The cumulative impact of multiple complications and various combinations of complications on outcomes was also examined.

RESULTS

The overall complication rate was 28.4% in 1,869 cases and the mortality rate was 2.6%. Median total charges was 41,905 dollars and median length of stay was 9 days. Overall 20.7% of patients had 1, 6.1% had 2, 1.2% had 3 and 0.42% had greater than 3 complications. At least 1 complication almost doubled the odds of mortality and increased median total charges and length of stay by 15,000 dollars and 4 days, respectively. We defined expected levels of increase in the various outcome measures with increasing numbers of complications. The combination of postoperative infection and respiratory complication had the greatest impact on mortality, while the combination of wound and urinary tract infection had the greatest impact on length of stay and total charges.

CONCLUSIONS

Although most patients undergoing cystectomy are older and have multiple comorbidities, the postoperative complications with the most significant impact were those directly related to surgery (primary complications). Secondary complications (cardiac, respiratory, vascular, etc) appear to have less of an impact on most common outcome measures. Hence, the greatest gains can be achieved by limiting primary complications. These data could be used to develop benchmarks of expected levels of primary and secondary complications after cystectomy.

Factors affecting outcomes after radical cystectomy in African Americans

BACKGROUND

Previous studies indicate that African Americans with bladder cancer have a worse outcome than Caucasians. Delay in seeking care and higher stage at presentation have been cited as possible reasons for the observed differences. The authors hypothesized that differences in hospital volume where patients undergo radical cystectomy may be responsible for race-based differences in outcomes after the procedure.

METHODS

The authors analyzed data from the Health Care Cost and Utilization Project and identified 4862 patients who had undergone radical cystectomy between 1998 and 2002. In-hospital mortality, complications, and length of stay (LOS) in hospital were compared between patients grouped by race. Hospitals were categorized into tertiles by the average number of radical cystectomies performed per year (1-4 radical cystectomies, 5-10 radical cystectomies, and >10 radical cystectomies). Univariate and multivariate analyses were performed to determine predictors of mortality, complications, LOS, and the likelihood that patients would undergo cystectomy at a high/medium-volume hospital.

RESULTS

African Americans had the highest in-patient mortality, complications, and LOS after radical cystectomy. They also were the least likely to undergo radical cystectomy at a high/medium-volume hospital. When the analyses were controlled for potential confounding factors, there was no difference in in-hospital mortality by race, but differences persisted in the other 3 outcome variables. African Americans had higher odds of complications (odds ratio [OR], 1.57; P = .001), longer LOS (25%; P = .001), and lower odds of undergoing cystectomy at a high/medium-volume hospital (OR, 0.74; P = .03) compared with Caucasians.

CONCLUSIONS

Race was an important factor in determining outcomes after radical cystectomy for bladder cancer. African Americans were less likely to undergo cystectomy at a high-volume hospital, thereby placing them at a higher risk of postoperative complications which ultimately may affect their survival.

Toward optimal recording of surgical complications: Concurrent tracking compared to the discharge data set

BACKGROUND

Information extracted from the hospital discharge data set is used increasingly for outcomes research and for benchmarking hospital and provider performance. The accuracy of these data in detecting vascular complications has never been validated.

METHODS

We compared morbidity and mortality data derived from the hospital discharge data set to similar data recorded concurrently by our Surgical Activity Tracking System (SATS) for 1 year on the vascular surgery service.

RESULTS

Of 798 total admissions, no complications were detected by either system in 598 admissions (75%). In 200 admissions (25%), there were 335 complications, including 24 deaths (3.0%), that occurred either in-hospital or within 30 days of the date of operation or the date of discharge for nonoperative admissions. Of the 335 complications, 180 (53.7%) were recorded by both systems; the SATS missed 59 complications recorded in the hospital discharge data set (17.6%), whereas the hospital discharge data set missed 96 complications recorded in the SATS (28.7%, P = .003). Of the 289 in-hospital complications, the SATS recorded 230 (79.5%), whereas the hospital discharge data set recorded 229 (79.2%). Of the 24 deaths, the hospital discharge data set missed 6 that occurred after discharge but within the 30-day reporting period

CONCLUSIONS

Both systems are not completely accurate for tracking inpatient complications. The SATS was more representative than the hospital discharge data set in capturing 30-day morbidity and mortality. An amalgamation of the 2 systems would provide more optimal tracking of complications.

Risk-adjusted rates for potentially avoidable reoperations were computed from routine hospital data

OBJECTIVES

Reoperations may reflect a suboptimal initial surgical treatment. The study aimed to develop a screening algorithm for those potentially avoidable, using only routinely collected hospital data and a prediction model to adjust rates for case-mix.

STUDY DESIGN AND SETTING

Data of a 3-year random sample of 7,370 therapeutic operations on inpatients, among which 833 were followed-up by a reoperation during the same stay. A review of medical records identified clearly avoidable and other potentially avoidable reoperations to develop and test the screening algorithm. A logistic prediction model of potentially avoidable reoperations was developed on one randomly chosen half of the data (about 9,000 interventions) and tested on the other half (cross-validation).

RESULTS

Two hundred thirty-seven interventions (3%) were followed by a potentially avoidable reoperation, among which 144 were clearly avoidable. The screening algorithm had a sensitivity of 75% and a specificity of 72%. Predictors of potentially avoidable reoperations were surgery categories, diagnosis related conditions, and experiencing prior surgery. The risk score, based on these variables, showed at once a satisfactory discriminative performance (C-statistic=0.76) and goodness-of-fit measure on the validation set.

CONCLUSION

The adjusted rate of potentially avoidable reoperations should be included in internal reporting of hospital quality indicators, but further validated in various settings.

Correlation of postoperative epidural analgesia on morbidity and mortality after colectomy in Medicare patients

STUDY OBJECTIVE

To examine, with a large database, the effect of postoperative epidural analgesia (vs systemic analgesia) on mortality after colectomy is unclear.

DESIGN

Retrospective cohort (database) design.

SETTING

Medicare beneficiaries undergoing elective colectomy.

PATIENTS

We examined a cohort of 12817 patients obtained from a 5% nationally random sample of Medicare beneficiaries from 1997 to 2001 who underwent elective partial excision of the large intestine.

INTERVENTIONS

Patients were divided into two groups depending on the presence or absence of billing for postoperative epidural analgesia (Current Procedural Terminology code 01996).

MEASUREMENTS

The primary outcomes assessed were death at 7 and 30 days after the procedure. The rates of major morbidity were also compared. Multivariate regression analysis incorporating race, gender, age, comorbidities, hospital size, hospital teaching status, and hospital technology status was performed to determine whether the presence of postoperative epidural analgesia had an independent effect on mortality or major morbidity.

MAIN RESULTS

Multivariate regression analysis revealed that there was no difference between the groups with regard to overall major morbidity; however, the presence of epidural analgesia was associated with a significantly lower odds of death at 7 days (odds ratio, 0.35; 95% confidence interval, 0.21-0.59; P < 0.0001) and 30 days (odds ratio, 0.54; 95% confidence interval, 0.42-0.70; P < 0.0001) after surgery.

CONCLUSIONS

The presence of postoperative epidural analgesia may decrease the odds of death after elective colectomy; however, the mechanism of such a benefit is not clear from our analysis.

Attributable cost of methicillin resistance: an issue that is difficult to evaluate

Estimating the consequences and the cost of methicillin resistance is a difficult challenge. Patients who develop methicillin-resistant ventilator-associated pneumonia (VAP) are very different from those who develop methicillin-sensitive VAP, and biased estimates are frequent. We reviewed some important confounding factors of which the reader should be aware.

Effect of postoperative epidural analgesia on morbidity and mortality after lung resection in Medicare patients

STUDY OBJECTIVE

To perform an analysis of the Medicare claims database in patients undergoing lung resection to determine whether there is an association between postoperative epidural analgesia and mortality.

DESIGN

Retrospective cohort (database) design.

SETTING

University hospital.

MEASUREMENTS

We examined a cohort of 3501 patients obtained from a 5% nationally random sample of 1997 to 2001 Medicare beneficiaries who underwent nonemergency segmental excision of the lung (International Classification of Diseases, 9th Revision, Clinical Modification codes 32.3 and 32.4). Patient data were divided into two groups depending on the presence or absence of billing for postoperative epidural analgesia (Current Procedural Terminology code 01996). The primary outcomes assessed were death at 7 and 30 days after the procedure. The rates of major morbidity (acute myocardial infarction, angina, cardiac dysrhythmias, heart failure, pneumonia, pulmonary edema, respiratory failure, deep venous thrombosis, pulmonary embolism, sepsis, acute renal failure, somnolence, acute cerebrovascular event, transient organic syndrome, and paralytic ileus) were also compared. Multivariate regression analysis incorporating race, gender, age, comorbidities, hospital size, hospital teaching status, and hospital technology status was performed to determine whether the presence of postoperative epidural analgesia had an independent effect on mortality or major morbidity.

MAIN RESULTS

Multivariate regression analysis showed that the presence of epidural analgesia was associated with a significantly lower odds of death at 7 days (odds ratio, 0.39; 95% confidence interval, 0.19-0.80; P = 0.001) and 30 days (odds ratio, 0.53; 95% confidence interval, 0.35-0.78; P = 0.002) after surgery. There was no difference between the groups with regard to overall major morbidity.

CONCLUSIONS

Postoperative epidural analgesia may contribute to lower odds of death after segmental excision of the lung, although the mechanism of such a benefit is not clear from our analysis.

Complications after radical cystectomy: Analysis of population-based data

OBJECTIVES

To determine the morbidity and mortality from radical cystectomy in a nationally representative population-derived sample. Complications after radical cystectomy have been reported from large single-institution series but population-based representative data are lacking.

METHODS

All patients undergoing radical cystectomy for bladder cancer were identified from the National Inpatient Sample data set of the Health Care Utilization Project (1998 to 2002). The prevalence of different complications coded according to the International Classification of Diseases, version 9, after cystectomy were determined. Independent hospital and patient-related factors associated with the occurrence of a complication were determined by logistic regression analysis. The prevalence of complication by type and frequency were compared with that in other large reported series.

RESULTS

The in-hospital mortality rate was 2.57%, and at least one complication other than death occurred in 28.4% of patients. These rates were comparable to those reported in published studies. Younger patients had a lower likelihood of complications. Younger patients and those undergoing cystectomy at large bed size, urban, teaching hospitals were less likely to have secondary complications after surgery, and younger patients, women, and those undergoing cystectomy at high-volume hospitals were less likely to have primary complications directly related to their surgery.

CONCLUSIONS

The overall morbidity and mortality rates after radical cystectomy in a population-based sample were comparable to those reported from individual centers. Larger centers in urban locations may have lower complication rates but only hospitals performing a high volume of cystectomies were associated with fewer primary surgery-related complications.

Public reporting of hospital outcomes based on administrative data: risks and opportunities

In the wake of findings from the Bundaberg Hospital and Forster inquiries in Queensland, periodic public release of hospital performance reports has been recommended. A process for developing and releasing such reports is being established by Queensland Health, overseen by an independent expert panel. This recommendation presupposes that public reports based on routinely collected administrative data are accurate; that the public can access, correctly interpret and act upon report contents; that reports motivate hospital clinicians and managers to improve quality of care; and that there are no unintended adverse effects of public reporting. Available research suggests that primary data sources are often inaccurate and incomplete, that reports have low predictive value in detecting "outlier" hospitals, and that users experience difficulty in accessing and interpreting reports and tend to distrust their findings.

Impact of nursing overtime on nurse-sensitive patient outcomes in New York hospitals, 1995-2000

During the past several years, nurses and their advocates have expressed concern about heavy use of overtime in hospitals and claimed that it undermines the quality of nursing care. Using staffing and discharge data covering 1995 to 2000 from 161 acute general hospitals in New York State, this study uses multi variate regression to analyze the relationship between overtime and the rates of six nurse-sensitive patient outcomes and mortality. We find an association of overtime with lower rates of mortality in medical and surgical patients but do not consider these findings definitive. Because overtime use is episodic and unit specific, further study of these issues using data that examines the occurrence of adverse events by unit during periods of heavy nurse overtime is recommended.

Relationship between patient complaints and surgical complications

BACKGROUND

Patient complaints are associated with increased malpractice risk but it is unclear if complaints might be associated with medical complications. The purpose of this study was to determine whether an association exists between patient complaints and surgical complications.

METHODS

A retrospective analysis of 16,713 surgical admissions was conducted over a 54 month period at a single academic medical center. Surgical complications were identified using administrative data. The primary outcome measure was unsolicited patient complaints.

RESULTS

During the study period 0.9% of surgical admissions were associated with a patient complaint. 19% of admissions associated with a patient complaint included a postoperative complication compared with 12.5% of admissions without a patient complaint (p = 0.01). After adjusting for surgical specialty, co-morbid illnesses and length of stay, admissions with complications had an odds ratio of 1.74 (95% confidence interval 1.01 to 2.98) of being associated with a complaint compared with admissions without complications.

CONCLUSIONS

Admissions with surgical complications are more likely to be associated with a complaint than surgical admissions without complications. Further research is necessary to determine if patient complaints might serve as markers for poor clinical outcomes.

Association of postoperative complications with hospital costs and length of stay in a tertiary care center

BACKGROUND

Postoperative complications are a significant source of morbidity and mortality. There are limited studies, however, assessing the impact of common postoperative complications on health care resource utilization.

OBJECTIVE

To assess the association of clinically important postoperative complications with total hospital costs and length of stay (LOS) in patients undergoing noncardiac surgery.

METHODS

We determined total hospital costs and LOS in all patients admitted to a single tertiary care center between July 1, 1996 and March 31, 1998 using a detailed administrative hospital discharge database. Total hospital costs and LOS were adjusted for preoperative and surgical characteristics.

RESULTS

Of 7,457 patients who underwent noncardiac surgery, 6.9% developed at least 1 of the postoperative complications. These complications increased hospital costs by 78% (95% confidence interval [CI]: 68% to 90%) and LOS by 114% (95% CI: 100% to 130%) after adjustment for patient preoperative and surgical characteristics. Postoperative pneumonia was the most common complication (3%) and was associated with a 55% increase in hospital costs (95% CI: 42% to 69%) and an 89% increase in LOS (95% CI: 70% to 109%).

CONCLUSIONS

Postoperative complications consume considerable health care resources. Initiatives targeting prevention of these events could significantly reduce overall costs of care and improve patient quality of care.

Accidental Iatrogenic Pneumothorax in Hospitalized Patients

OBJECTIVE

Iatrogenic pneumothorax (IP) is an inherent risk to patients who undergo procedures that involve the intentional puncturing of the lung. IP also could occur accidentally to patients who do not undergo such procedures; such accidental IP (AIP) is suggestive of lapses in safe care. This study assessed the risk for AIP in patients hospitalized with specific diagnoses who underwent specific procedures.

RESEARCH DESIGN

We analyzed 7.5 million discharge abstracts from 994 short-term acute care hospitals across 28 states in 2000 in the Agency for Healthcare Research and Quality (AHRQ), Healthcare Cost and Utilization Project Nationwide Inpatient Sample. AHRQ Patient Safety Indicators (PSIs) were used to identify AIP. AIP incidences and associated diagnoses and procedures were explored.

RESULTS

Patients who were admitted for pleurisy, cancer of the kidney and renal pelvis, or conduction disorders and complications of cardiac devices had the highest rates of developing AIP during hospitalization, with AIP rates at 2.24%, 1.14%, and 0.83% respectively. The procedure-specific rates for AIP varied from 2.68% for patients who underwent thoracentesis to 1.30% for those who underwent nephrectomy, to 0.06% for those who underwent gastrostomy. Thoracentesis appeared to be a high-risk procedure for patients who were admitted for secondary malignancies, pleurisy, or pneumonia, with AIP rates at 3.76%, 3.13%, and 2.28%, respectively.

CONCLUSIONS

Although AIP is most common after thoracentesis, it is a substantial threat to patients undergoing a wide range of procedures.

Standards for Statistical Models Used for Public Reporting of Health Outcomes

With the proliferation of efforts to report publicly the outcomes of healthcare providers and institutions, there is a growing need to define standards for the methods that are being employed. An interdisciplinary writing group identified 7 preferred attributes of statistical models used for publicly reported outcomes. These attributes include (1) clear and explicit definition of an appropriate patient sample, (2) clinical coherence of model variables, (3) sufficiently high-quality and timely data, (4) designation of an appropriate reference time before which covariates are derived and after which outcomes are measured, (5) use of an appropriate outcome and a standardized period of outcome assessment, (6) application of an analytical approach that takes into account the multilevel organization of data, and (7) disclosure of the methods used to compare outcomes, including disclosure of performance of risk-adjustment methodology in derivation and validation samples.

Cystectomy for muscle-invasive bladder cancer: patterns and outcomes of care in the Medicare population

OBJECTIVES

To describe the population-based patterns of care among patients with muscle-invasive bladder cancer.

METHODS

A retrospective cohort study using the Surveillance, Epidemiology and End Results (SEER)-Medicare database identified 4664 patients aged 65 years or older with muscle-invasive bladder cancer diagnosed between 1991 and 1999. The use of particular treatment modalities was evaluated according to the clinical and demographic characteristics available in the SEER-Medicare database.

RESULTS

Considerable variation was found in the treatments delivered to the cohort members. Overall, 39% had undergone cystectomy; 30% of Stage II, 57% of Stage III, and 38% of Stage IV patients underwent this operation within 6 months of diagnosis. The frequency of resection declined with age, such that 55% of patients aged 65 to 69 years and 27% of those aged 80 to 84 years underwent cystectomy. For 36% of Stage II, 18% of Stage III, and 27% of Stage IV patients, no evidence was found of surgery, chemotherapy, or radiotherapy within 6 months of diagnosis. Other management strategies included chemotherapy alone (14% Stage II, 6% Stage III, and 12% Stage IV), radiotherapy alone (11% for each stage), or combined modality chemoradiotherapy (10% Stage II, 8% Stage III, and 12% Stage IV). Multivariate analyses suggested that cystectomy conferred a survival advantage.

CONCLUSIONS

A marked heterogeneity exists in the strategies used to treat muscle-invasive bladder cancer. The extent to which this variation can be attributed to the lack of informative clinical trials, the presence of comorbid illness, patient or physician preferences, or access to care warrants further evaluation.

Extracranial—intracranial bypass in the treatment of occlusive cerebrovascular disease and intracranial aneurysms in the United States between 1992 and 2001: a population-based study

Object. The authors assessed the results of extracranial—intracranial (EC—IC) bypass surgery in the treatment of occlusive cerebrovascular disease and intracranial aneurysms in the US between 1992 and 2001 by using population-based methods.

Methods. This is a retrospective cohort study based on data from the Nationwide Inpatient Sample (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality, Rockville, MD). Five hundred fifty-eight operations were performed at 158 hospitals by 115 identified surgeons. The indications for surgery were cerebral ischemia in 74% of the operations (2.4% mortality rate), unruptured aneurysms in 19% of the operations (7.7% mortality rate), and ruptured aneurysms in 7% of the operations (21% mortality rate). Overall, 4.6% of the patients died and 4.7% of the patients were discharged to long-term facilities, 16.4% to short-term facilities, and 74.2% to their homes. The annual number of admissions in the US increased from 190 per year (1992–1996) to 360 per year (1997–2001), whereas the mortality rates increased from 2.8% (1992–1996) to 5.7% (1997–2001).

The median annual number of procedures was three per hospital (range one–27 operations) or two per surgeon (range one–21 operations). For 29% of patients, their bypass procedure was the only one recorded at their particular hospital during that year; for these institutions the mean annual caseload was 0.4 admissions per year. For 42% of patients, their particular surgeon performed no other bypass procedure during that year. Older patient age (p < 0.001) and African-American race (p = 0.005) were risk factors for adverse outcome. In a multivariate analysis in which adjustments were made for age, sex, race, diagnosis, admission type, geographic region, medical comorbidity, and year of surgery, high-volume hospitals less frequently had an adverse discharge disposition (odds ratio 0.54, p = 0.03).

Conclusions. Most EC—IC bypasses performed in the US during the last decade were performed for occlusive cerebrovascular disease. Community mortality rates for aneurysm treatment including bypass procedures currently exceed published values from specialized centers and, during the period under study, the mortality rates increased with time for all diagnostic subgroups. This technically demanding procedure has become a very low-volume operation at most US centers.

Accuracy of reporting maternal in-hospital diagnoses and intrapartum procedures in Washington State linked birth records

While the impact of maternal morbidities and intrapartum procedures is a common topic in perinatal outcomes research, the accuracy of the reporting of these variables in the large administrative databases (birth certificates, hospital discharges) often utilised for such research is largely unknown. We conducted this study to compare maternal diagnoses and procedures listed on birth certificates, hospital discharge data, and birth certificate and hospital discharge data combined, with those documented in a stratified random sample of hospital medical records of 4541 women delivering liveborn infants in Washington State in 2000. We found that birth certificate and hospital discharge data combined had substantially higher true positive fractions (TPF, proportion of women with a positive medical record assessment who were positive using the administrative databases) than did birth certificate data alone for labour induction (86% vs. 52%), cephalopelvic disproportion (83% vs. 35%), abruptio placentae (85% vs. 68%), and forceps-assisted delivery (89% vs. 55%). For procedures available only in hospital discharge data, TPFs were generally high: episiotomy (85%) and third and fourth degree vaginal lacerations (91%). Except for repeat caesarean section without labour (TPF, 81%), delivery procedures available only in birth certificate data had low TPFs, including augmentation (34%), repeat caesarean section with labour (61%), and vaginal birth after caesarean section (62%). Our data suggest that researchers conducting perinatal epidemiological studies should not rely solely on birth certificate data to detect maternal diagnoses and intrapartum procedures accurately.

Population-Based Assessment of Surgical Treatment Trends for Patients With Melanoma in the Era of Sentinel Lymph Node Biopsy

Purpose

The surgical staging of melanoma dramatically changed with the introduction of sentinel lymph node (SLN) biopsy. In this study, Surveillance, Epidemiology, and End Results (SEER) data were examined to determine how surgical treatment is being carried out and whether SLN biopsy is being performed in melanoma patients in conformance with National Comprehensive Cancer Network (NCCN) guidelines.

Patients and Methods

The SEER database (1998 to 2001) was searched for all patients with invasive melanoma. NCCN guidelines were used to define optimal stage-specific surgical treatment. Treatment trends in patients with stages I to III disease were summarized, and multivariate analyses were performed to identify factors associated with nonadherence with treatment guidelines.

Results

A total of 21,867 melanoma patients were identified; 18,499 of these patients met the inclusion criteria. The number of patients diagnosed with stage III melanoma increased by 55.7% over the study period, and this corresponded to a 53% increase in the number of SLN biopsies performed annually. The odds ratios for nonadherence were 2.32, 2.27, and 1.54 for stages IB, II, and III disease, respectively, compared with stage IA melanoma. Multivariate analyses revealed that age more than 65 years, marital status, minority populations, and primary tumor location were associated with nonadherence with guidelines. Treatment patterns among tumor registries also varied significantly.

Conclusion

Stage migration is evident in the SEER registries in consort with increasing use of SLN biopsy. Although treatment trends are improving, SLN biopsy continues to be underused, particularly in the elderly and minority populations, in patients with truncal and head/neck melanomas, and also in some geographic regions of the United States.

Accuracy of coding for possible warfarin complications in hospital discharge abstracts

BACKGROUND

Hospital discharge abstracts could be used to identify complications of warfarin if coding for bleeding and thromboembolic events are accurate.

OBJECTIVES

To measure the accuracy of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9CM) codes for bleeding and thromboembolic diagnoses.

SETTING

University affiliated, tertiary care hospital in Ottawa, Canada.

PATIENTS

A random sample of patients discharged between September 1999 and September 2000 with an ICD-9-CM code indicating a bleeding or thromboembolic diagnosis.

METHODS

Gold-standard coding was determined by a trained chart abstractor using explicit standard diagnostic criteria for bleeding, major bleeding, and acute thromboembolism. The abstractor was blinded to the original coding. We calculated the sensitivity, specificity, positive, and negative predictive values of the original ICD-9CM codes for bleeding or thromboembolism diagnoses.

RESULTS

We reviewed 616 medical records. 361 patients (59%) had a code indicating a bleeding diagnosis, 291 patients (47%) had a code indicating a thromboembolic diagnosis and 36 patients (6%) had a code indicating both. According to the gold standard criteria, 352 patients experienced bleeding, 333 experienced major bleeding, and 188 experienced an acute thromboembolism. For bleeding, the ICD-9CM codes had the following sensitivity, specificity, positive and negative predictive values [95% CI]: 93% [90-96], 88% [83-91], 91% [88-94], and 91% [87-94], respectively. For major bleeding, the ICD-9CM codes had the following sensitivity, specificity, positive and negative predictive values: 94% [91-96], 83% [78-87], 87% [83-90], and 92% [88-95], respectively. For thromboembolism, the ICD-9CM codes had the following sensitivity, specificity, positive and negative predictive values: 97% [94-99], 74% [70-79], 62% [57-68], and 98% [96-99], respectively. By selecting a sub-group of ICD-9CM codes for thromboembolism, the positive predictive value increased to 87%.

CONCLUSION

In our centre, the discharge abstract could be used to identify and exclude patients hospitalized with a major bleed or thromboembolism. If coding quality for bleeding is similar in other hospitals, these ICD-9-CM diagnostic codes could be used to study population-based warfarin-associated hemorrhagic complications using administrative databases.

Resident work hour limits and patient safety

OBJECTIVE

This study evaluates the effect of resident physician work hour limits on surgical patient safety.

BACKGROUND

Resident work hour limits have been enforced in New York State since 1998 and nationwide from 2003. A primary assumption of these limits is that these changes will improve patient safety. We examined effects of this policy in New York on standardized surgical Patient Safety Indicators (PSIs).

METHODS

An interrupted time series analysis was performed using 1995 to 2001 Nationwide Inpatient Sample data. The intervention studied was resident work hour limit enforcement in New York teaching hospitals. PSIs included rates of accidental puncture or laceration (APL), postoperative pulmonary embolus or deep venous thrombosis (PEDVT), foreign body left during procedure (FB), iatrogenic pneumothorax (PTX), and postoperative wound dehiscence (WD). PSI trends were compared pre- versus postintervention in New York teaching hospitals and in 2 control groups: New York nonteaching hospitals and California teaching hospitals.

RESULTS

A mean of 2.6 million New York discharges per year were analyzed with cumulative events of 33,756 (APL), 36,970 (PEDVT), 1,447 (FB), 10,727 (PTX), and 2,520 (WD). Increased rates over time (expressed per 1000 discharges each quarter) were observed in both APL (0.15, 95% confidence interval, 0.09-0.20, P<0.05) and PEDVT (0.43, 95% confidence interval, 0.03-0.83, P<0.05) after policy enforcement in New York teaching hospitals. No changes were observed in either control group for these events or New York teaching hospital rates of FB, PTX, or WD.

CONCLUSIONS

Resident work hour limits in New York teaching hospitals were not associated with improvements in surgical patient safety measures, with worsening trends observed in APL and PEDVT corresponding with enforcement.

Assessing patient safety in the United States: challenges and opportunities

BACKGROUND

In 1999, the US Congress mandated the Agency for Healthcare Research and Quality (AHRQ), Department of Health and Human Services (DHHS), to report annually to the nation about healthcare quality. One chapter in the National Healthcare Quality Report (NHQR) is focused on patient safety.

OBJECTIVES

The objectives of this study were to describe the challenges in reporting the national status on patient safety for the first NHQR and discuss emerging opportunities to improve the comprehensiveness and reliability of future reporting.

RESEARCH DESIGN

This study is a selective review of definitions, frameworks, data sources, measures, and emerging developments for assessing patient safety in the United States.

RESULTS

Available data and measures for patient safety assessment in the nation are inadequate, especially for comparing regions and subpopulations and for trend analysis. However, many opportunities are emerging from the recently increased investments in patient safety research and many ongoing safety improvement efforts in the private sector and at the federal, state, and local government levels.

CONCLUSION

There are many challenges in assessing national performance on patient safety today. Ongoing developments on multiple fronts will provide data and measures for more accurate and more comprehensive assessments of patient safety for future NHQRs.

Revision total knee arthroplasty complication rates in Northern Illinois

A paucity of population-based data exist which describe the rapid growth of revision total knee arthroplasties, changes in patient characteristics, or the association of hospital volume with complication rates. We analyzed whether inpatient complications for 2986 revision knee arthroplasties done on patients admitted to 63 hospitals in northern Illinois from 1993-1999 were correlated with volume of revision total knee arthroplasties. Coded complication rates for hospitals with less than seven, seven to 14, or greater than 14 annual procedures were compared using logistic regression to control for clinical and demographic characteristics of patients, hospital teaching status, and the proportion of the hospitals' patients discharged to rehabilitation facilities. Revision total knee arthroplasties increased 59%, and the overall complication rate declined from 9.3% during 1993-1996 to 7.3% during 1997-1999 (p = .04). When compared with the lowest volume hospitals, medium-volume hospitals had higher complication rates, whereas the highest volume hospitals were not significantly different. The absence of volume-outcome effects may be related to the relatively high volume of primary knee arthroplasties done at almost all area hospitals, surgeon group coverage across multiple hospitals, and the small annual number of revision total knee arthroplasties done during these years.

Readmissions for venous thromboembolism: expanding the definition of patient safety indicators

BACKGROUND

The Agency for Healthcare Research and Quality (AHRQ) defines its venous thromboembolism (VTE) patient safety indicator (PSI) as surgical cases with a secondary diagnosis of pulmonary embolism or deep vein thrombosis. Short-term readmissions for VTE are excluded because most state administrative databases are unable to track readmissions.

METHODS

Patients meeting the AHRQ VTE PSI definition and those readmitted with a VTE principal diagnosis within 30 days of a prior surgical hospitalization were identified on the basis of inpatient discharge data.

RESULTS

A total of 4,906 surgical discharges in New York met the AHRQ VTE PSI definition in 2001. An additional 1,059 cases of VTE were found when surgical patients with a short-term readmission for VTE were identified. Patients readmitted with VTE were less likely to die but were more likely to have a pulmonary embolism and were more likely to be white and non-Hispanic compared to those who met the AHRQ VTE PSI definition.

DISCUSSION

Short-term readmissions for VTE represent potentially important cases to capture when monitoring adverse events. Prophylaxis, monitoring, and patient education may be required after hospital discharge to prevent or treat VTE as early as possible. Data systems that can track patients across multiple admissions to identify complications resulting in short-term readmissions are needed.

Use of surgery among elderly patients with stage IV colorectal cancer

PURPOSE

The role of surgery to remove the primary tumor among patients with stage IV colorectal cancer (CRC) is controversial. The purpose of this study was to evaluate surgical practice patterns for patients > or = 65 years of age with stage IV CRC in a US population-based cohort.

PATIENTS AND METHODS

We used the Surveillance, Epidemiology, and End Results-Medicare-linked database to evaluate the patterns of cancer treatment for 9,011 Medicare beneficiaries presenting with stage IV CRC from 1991 to 1999. Patients were categorized according to whether they had primary-cancer-directed surgery (CDS) or no CDS within 4 months of diagnosis. The use of other treatment modalities, including metastasectomy, chemotherapy, and radiation, was evaluated in relationship to whether patients belonged to the CDS or no CDS group.

RESULTS

Seventy-two percent (6,469 of 9,011) of patients received CDS, and their 30-day postoperative mortality was 10%. Patients with left-sided or rectal lesions, patients older than age 75 years, blacks, and those of lower socioeconomic status were less likely to undergo CDS; but even among those older than age 75, the CDS rate was 69% (3,378 of 4,909). In contrast, chemotherapy use was less common (47% for patients who had CDS and 31% for those who did not). Metastasectomy was rare; only 3.9% of patients underwent these operations at any point from diagnosis to death.

CONCLUSION

Palliative resection of the primary tumor is often performed for elderly US patients with stage IV colorectal cancer. This practice pattern merits re-evaluation, given the improvement in the efficacy of systemic chemotherapy.

Validity of procedure codes in International Classification of Diseases, 9th revision, clinical modification administrative data

BACKGROUND

Administrative hospital discharge data are widely used to assess quality of care in patients undergoing certain procedures. However, little is known about the validity of administrative coding of procedure data. We conducted a detailed chart review to evaluate the accuracy and completeness of information on procedures in administrative data.

METHODS

We randomly selected 1200 hospital separations in the period April 1, 1996, to March 31, 1997, from administrative discharge data of 3 acute adult hospitals in Calgary, Alberta, Canada. Each separation record in administrative data contains up to 10 procedure coding fields. The corresponding medical charts were reviewed for recording presence or absence of procedures. We then determined sensitivity to quantify the accuracy of coding presence of procedures in administrative data when these are present in the chart data (criterion standard).

RESULTS

The agreement between the 2 databases varied greatly across 35 procedures studied. The sensitivity ranged from 0% to 94%. Of 6 major procedures studied, validity of coding was generally good, with 5 procedures having coding sensitivity of 69% and over and only 1 (lysis of peritoneal adhesion) with a low sensitivity of 41%. In contrast, many minor procedures had low sensitivities. Of 29 minor procedures studied, sensitivity was lower than 50% for 15 procedures, between 50% and 79% for 10, and 80% and over for 4.

CONCLUSION

Validity of information on procedures in administrative discharge data appears to be related to type of procedures. Major procedures that are usually performed in operating rooms are reasonably well-coded. Meanwhile, minor procedures that are routinely performed on wards or in radiology departments are generally undercoded.

Time trends in warfarin-associated hemorrhage

The annual incidence of warfarin-related bleeding at Brigham and Women's Hospital increased from 0.97/1,000 patient admissions in the first time period (January 1995 to October 1998) to 1.19/1,000 patient admissions in the second time period (November 1998 to August 2002) of this study. The proportion of patients with major and intracranial bleeding increased from 20.2% and 1.9%, respectively, in the first time period, to 33.3% and 7.8%, respectively, in the second.

Patient safety: effect of institutional protocols on adverse events related to feeding tube placement in the critically ill1 1No competing interests declared

BACKGROUND

Inadvertent passage of a nasoenteric feeding tube into the tracheobronchial tree can result in pneumothorax. Measures requiring feeding tube passage to 35 cm only followed by a radiograph to verify intraesophageal placement and creation of a specialized placement team were implemented to decrease the incidence of procedure-related pneumothorax. This study evaluates the effectiveness of our safety measures.

STUDY DESIGN

Radiology reports from January 2000 through July 2003 were searched by computer with an algorithm designed to detect feeding tube placements possibly associated with the complication of intrabronchial placement or pneumothorax. Results were manually examined to eliminate false positives and verify causality.

RESULTS

Feeding tubes were placed in 4,190 unique patients during the study period; 87 patients had an intrabronchial malposition, and 9 experienced a pneumothorax caused by their feeding tube. The safety measures resulted in a significant decrease in procedure-related pneumothorax (0.09% versus 0.38%, p < 0.05), and a decrease in pneumothorax among patients with an intrabronchial placement (3% versus 27%, p < 0.05). More than two-thirds of patients with a misplaced tube had an endotracheal tube or tracheostomy, illustrating that such patients are not protected. Repeated malposition in the same patient was surprisingly common; 32% of patients with one intrabronchial misplacement ultimately had multiple misplacements. The risk of pneumothorax increased with misplacement at night (p < 0.05) and increased exponentially with each additional misplacement (p < 0.05).

CONCLUSIONS

Creating a specialized placement team, and initiating the safety measure of limiting feeding tube placement to 35 cm and obtaining a radiograph before full advancement reduced the incidence of procedure-related pneumothorax.

Detecting adverse events for patient safety research: a review of current methodologies

Promoting patient safety is a national priority. To evaluate interventions for reducing medical errors and adverse event, effective methods for detecting such events are required. This paper reviews the current methodologies for detection of adverse events and discusses their relative advantages and limitations. It also presents a cognitive framework for error monitoring and detection. While manual chart review has been considered the "gold-standard" for identifying adverse events in many patient safety studies, this methodology is expensive and imperfect. Investigators have developed or are currently evaluating, several electronic methods that can detect adverse events using coded data, free-text clinical narratives, or a combination of techniques. Advances in these systems will greatly facilitate our ability to monitor adverse events and promote patient safety research. But these systems will perform optimally only if we improve our understanding of the fundamental nature of errors and the ways in which the human mind can naturally, but erroneously, contribute to the problems that we observe.

Use of emergency department chief complaint and diagnostic codes for identifying respiratory illness in a pediatric population

OBJECTIVES

(1) To determine the value of emergency department chief complaint (CC) and International Classification of Disease diagnostic codes for identifying respiratory illness in a pediatric population and (2) to modify standard respiratory CC and diagnostic code sets to better identify respiratory illness in children.

METHODS

We determined the sensitivity and specificity of CC and diagnostic codes by comparing code groups with a criterion standard. CC and diagnostic codes for 500 pediatric emergency department patients were retrospectively classified as respiratory or nonrespiratory. Respiratory diagnostic codes were further classified as upper or lower respiratory. The criterion standard was a blinded, reviewer-assigned illness category based on history, physical examination, test results, and treatment. We also modified our respiratory code sets to better identify respiratory illness in this population.

RESULTS

Four hundred ninety-six charts met inclusion criteria. By the criterion standard, 87 (18%) patients had upper and 47 (10%) had lower respiratory illness. The specificity of CC and diagnostic codes groups was >0.97 [95% confidence interval (CI) 0.95-0.98]. The code group sensitivities were as follows: CC was 0.47 (95% CI 0.38-0.55), upper respiratory diagnostic was 0.56 (95% CI 0.45-0.67), lower respiratory diagnostic was 0.87 (95% CI 0.74-0.95), and combined CC and/or diagnostic was 0.72 (95% CI 0.63-0.79). Modifying the respiratory code sets to better identify respiratory illness increased sensitivity but decreased specificity.

CONCLUSIONS

Diagnostic and CC codes have substantial value for emergency department syndromic surveillance. Adapting our respiratory code sets to a pediatric population forced a tradeoff between sensitivity and specificity.

International Classification of Diseases-9th revision coding for preeclampsia: how accurate is it?

OBJECTIVE

The purpose of this study was to evaluate the accuracy of the International Classification of Diseases-9th revision codes for preeclampsia and eclampsia.

STUDY DESIGN

The University of Illinois Medical Center at Chicago discharge database was used to identify 135 women from 1999 through 2001 whose disease was coded as having preeclampsia or eclampsia. With American College of Obstetrics and Gynecology criteria as the gold standard, the diagnosis that was determined through chart review was compared with the International Classification of Diseases-9th revision code that was present in the discharge database. Patients were classified as true cases if the International Classification of Diseases-9th revision code matched the American College of Obstetricians and Gynecologists diagnosis; the positive predictive value of the code was then calculated.

RESULTS

The overall positive predictive value for the complete sample was only 54%, but the positive predictive value for severe preeclampsia was 84.8%, which was high compared with mild preeclampsia (45.3%) and eclampsia (41.7%). Diagnostic (clinician) error was the most common reason for miscoding error.

CONCLUSION

The findings suggest that International Classification of Diseases-9th revision codes for preeclampsia/eclampsia vary greatly in their accuracy of diagnosis. Therefore, a review of medical records is required when data are being gathered on the incidence of preeclampsia and eclampsia.

Identifying undiagnosed primary immunodeficiency diseases in minority subjects by using computer sorting of diagnosis codes

BACKGROUND

Primary immunodeficiency diseases occur in all populations, but these diagnoses are rarely made in minority subjects in the United States.

OBJECTIVE

We sought to develop and validate a method to identify patients without diagnoses but with immunodeficiency in an urban hospital with a substantial minority patient population.

METHODS

We developed a scoring algorithm on the basis of International Classification of Disease, Ninth Revision (ICD-9) codes to identify all hospitalized patients age 60 years or less who had been given a diagnosis of 2 or more of 174 ICD-9-coded complications associated with immunodeficiency. Codes were weighted for severity and expressed as a sum for all admissions between October 1, 1995, and December 31, 2002. Patients with, for example, cancer or HIV or those after transplantation or major surgery were excluded. Demographic features of subjects with aggregated ICD-9 codes suggestive of immunodeficiency were compared with those of other inpatients; 59 computer-selected subjects were then tested for immune defects.

RESULTS

The computer-identified group contained 533 patients (0.4% of all inpatients), who had been hospitalized 2683 times. The median age was 6.6 years. Sixty-five percent were African American or Hispanic, and 61% were insured by Medicaid, which is significantly more than other inpatients younger than 60 years of age (median age, 32.6 years; 37% minority, 27% insured by Medicaid; P<.0001). Primary immunodeficiency was found in 17 (29%) of the 59 subjects tested. Thirteen other patients had secondary immune defects, and 86% of immunodeficient subjects were Hispanic or African American.

CONCLUSIONS

An ICD-9-based scoring algorithm identifies patients demographically different from other hospitalized subjects who have multiple illnesses suggestive of immunodeficiency. This group contains undiagnosed minority patients with immunodeficiency.