Utility of DRG and ICD-9-CM classification codes for the study of transfusion issues. Transfusions in patients with digestive diseases

Red alert - a new perspective on patterns of blood use in the South Australian public sector

OBJECTIVES

In 2006 South Australia had a red cell issue rate, measured as product issues per 1000 population, 22.4% higher than the national average. A pilot study was undertaken to investigate the disparity in issue rates between SA and the national average with a secondary aim of establishing information on SA red cell use.

METHODS

A linked electronic database was developed using clinical, epidemiological and red cell transfusion data within hospitals in the SA public sector. Aggregated red cell use across the SA public health sector was analysed by clinical variables such as Diagnosis Related Group (DRG), including specialty related groups (SRGs) and major diagnostic categories (MDCs). The DRGs that were associated with blood use were identified and applied to national hospital separations data in order to derive comparative blood utilisation rates for SA and Australia.

RESULTS

Although blood issue and usage by population measure showed a significant difference of 22.4 and 22.0% respectively between SA and Australia, when measured against weighted separations the differences reduced to 7.4 and 7.1% respectively.

CONCLUSION

This study showed the importance of analysing blood issues and utilisation on an activity adjusted basis rather than a raw per capita basis.

Transfusion rates vary significantly amongst Canadian medical centres

PURPOSE

To document variation of transfusion practice following repair of hip fracture or cardiac surgery, as well as those requiring intensive care following a surgical intervention or multiple trauma (high risk patients).

METHODS

We documented rates of allogeneic red cell transfusion in 41,568 patients admitted to 11 hospitals across Canada between August 1998 and August 2000 as part of a retrospective observational cohort study. In the subgroup of 7,552 patients receiving red cells, we also compared mean nadir hemoglobin concentrations from centre to centre.

RESULTS

The overall rate of red cell transfusion was 38.7%, and ranged from 23.8% to 51.9% across centres among the 41,568 perioperative and critically ill patients. Women were more likely to be transfused (43.7% vs 35.3%, P < 0.0001), with higher rates of transfusion in eight of 11 centres. Compared to a chosen reference hospital having a crude transfusion rate near the median, the adjusted odds of transfusion ranged from 0.44 to 1.53 overall, from 0.42 to 1.22 in patients undergoing a hip fracture repair, from 0.72 to 3.17 in cardiac surgical patients undergoing cardiac surgery, and from 0.27 to 1.11 in critically ill and trauma patients. In the 7,552 transfused patients, the mean adjusted nadir hemoglobin was 74.0 +/- 4.83 g x L(-1) overall, and ranged from 66.9 +/- 1.7 g x L(-1) to 84.5 +/- 1.6 g x L(-1) across centres. Similar differences among centres were observed amongst hip fracture patients (71.2 +/- 2.9 g x L(-1) to 82.8 +/- 1.7 g x L(-1)), cardiac surgical patients (65.7 +/- 1.1 g x L(-1) to 77.3 +/- 1.0 g x L(-1)) and critically ill and trauma patients (66.1 +/- 3.04 g x L(-1) to 87.5 +/- 2.5 g x L(-1)).

CONCLUSION

We noted significant differences in the rates of red cell transfusion and nadir hemoglobin concentrations in various surgical and critical care settings.

A study of blood usage by diagnoses in a Korean university hospital

BACKGROUND AND OBJECTIVES

There is paucity of comprehensive data on the blood usage with regard to diagnostic categories of Asian recipients. The purpose of this study is to analyse data for blood usage in a korean university hospital in order to obtain additional information on transfusion practices in relation to diagnoses.

MATERIALS AND METHODS

Data of information on patients discharged during the period from March 1996 to February 2002, who have received packed red blood cells (RBC), fresh frozen plasmas (FFP), and platelet components (PLT) were extracted from the computerized registers. We used only the principal four-digit diagnostic categories of the Tenth Revision of International Classification of Diseases.

RESULTS

A total of 397 489 units of blood components (RBC 171 916 units; FFP 69 301 units; and PLT 156 272 units) were transfused for 17.2% of all discharged patients. Acute myeloid leukaemia, liver cell carcinoma, advanced gastric cancer, alcoholic or other unspecified cirrhosis of liver were the top 5 diagnoses related with the highest usage of blood component.

CONCLUSIONS

The results showed a different blood usage pattern compared to those of previous studies. These provide a baseline transfusion practice at our institution, and the data would help in predicting future blood needs in a variety of diagnostic categories.

Accuracy of identification of patients with immune thrombocytopenic purpura through administrative records: a data validation study

Administrative data are commonly used to estimate the prevalence of a disease, but the validity of the coding system needs to be evaluated before its use. We assessed the validity of the International Classification of Disease, 9(th) version, Clinical Modification (ICD-9-CM) code of 287.3 for identifying patients with immune thrombocytopenic purpura (ITP). Administrative data from inpatients and outpatients seen were retrieved if the patient or insurer was billed with one of three ICD-9-CM codes for thrombocytopenic disorders, 287.3, 287.4, and 287.5, as a primary or secondary diagnosis; or was physician-identified as having ITP. The electronic medical records for these patients were systematically reviewed to identify patients with ITP and with non-ITP diagnoses. Sensitivity, specificity, positive and negative predictive values, and kappa scores were calculated separately for inpatients and outpatients. Four-hundred eighteen records were reviewed. Among inpatients, the sensitivity of code 287.3 for indicating a diagnosis of ITP was 100% [95% confidence interval 94-100%]. The specificity was 89% [95% confidence interval 84-94%]. The percent agreement was 92%, and the kappa statistic was 0.80. For outpatients, the sensitivity of the billing code 287.3 was 84% [95% confidence interval 76-91%], a conservative estimate because of how the patients with other diagnoses were selected. The specificity for outpatients was 66% [95% confidence interval 56-76%]. ICD-9-CM code 287.3 in administrative billing data is likely to be sufficiently sensitive and specific, particularly when inpatient data are used, for the estimation of the prevalence of ITP.

Red blood cell transfusion strategies

Although the hemoglobin level of 100 g/L has been used for many years as the allogeneic red blood cell (RBC) transfusion trigger, current evidence indicates that for most patients a more restrictive transfusion strategy is at least as effective as and possibly superior to a liberal transfusion strategy. Moreover, the available data indicate that the use of smaller volumes of allogeneic RBCs may be associated with decreased risk of morbidity and mortality. Thus several recent studies indicate that the use of more restrictive triggers than 100 g/L does not appear to adversely affect patient outcomes. Indeed, the majority of recently published RBC transfusion guidelines recommend a more conservative and cautious approach to allogeneic RBC transfusion practice, primarily to reduce the risk of transfusion-related adverse effects. However, the available transfusion trigger studies do not provide sufficient data to allow the claim that the improved outcomes observed are the sole result of the transfusion strategy used. It is possible that the results are the consequence of effects yet to be defined clearly. Additional studies will be necessary to determine the effects of RBC storage time and the presence of allogeneic leukocytes in allogeneic RBC transfusion practice. Nonetheless, the available data, together with detailed information about alternatives to blood product transfusions, will enable physicians to improve outcomes in transfused patients.

Variation in red cell transfusion practice in the intensive care unit: a multicentre cohort study

OBJECTIVES: To determine the degree of interinstitutional transfusion practice variation and reasons why red cells are administered in critically ill patients. STUDY DESIGN: Multicentre cohort study combined with a cross-sectional survey of physicians requesting red cell transfusions for patients in the cohort. STUDY POPULATION: The cohort included 5298 consecutive patients admitted to six tertiary level intensive care units in addition to administering a survey to 223 physicians requesting red cell transfusions in these units. MEASUREMENTS: Haemoglobin concentrations were collected, along with the number and reasons for red cell transfusions plus demographic, diagnostic, disease severity (APACHE II score), intensive care unit (ICU) mortality and lengths of stay in the ICU. RESULTS: Twenty five per cent of the critically ill patients in the cohort study received red cell transfusions. The overall number of transfusions per patient-day in the ICU averaged 0.95 +/- 1.39 and ranged from 0.82 +/- 1.69 to 1.08 +/- 1.27 between institutions (P < 0.001). Independent predictors of transfusion thresholds (pre-transfusion haemoglobin concentrations) included patient age, admission APACHE II score and the institution (P < 0.0001). A very significant institution effect (P < 0.0001) persisted even after multivariate adjustments for age, APACHE II score and within four diagnostic categories (cardiovascular disease, respiratory failure, major surgery and trauma) (P < 0.0001). The evaluation of transfusion practice using the bedside survey documented that 35% (202 of 576) of pre-transfusion haemoglobin concentrations were in the range of 95-105 g/l and 80% of the orders were for two packed cell units. The most frequent reasons for administering red cells were acute bleeding (35%) and the augmentation of O2 delivery (25%). CONCLUSIONS: There is significant institutional variation in critical care transfusion practice, many intensivists adhering to a 100g/l threshold, and opting to administer multiple units despite published guidelines to the contrary. There is a need for prospective studies to define optimal practice in the critically ill.

Variations in transfusion practice in neonatal intensive care

OBJECTIVE

To compare the transfusion practices between two neonatal intensive care units (NICUs) to assess the impact of local practice styles on the timing, number, and total volume of packed red cell transfusions in very low birth weight infants. To derive multivariate models to describe practice and to identify potential areas for improvement in the future.

METHODOLOGY

We reviewed phlebotomy losses and transfusion rates between two NICUs (A and B) for 270 consecutive admissions of birth weight < 1500 g. We stratified for birth weight and for illness severity by the Score for Neonatal Acute Physiology (SNAP). Measures of short-term outcome were compared. We derived multivariate models to describe and compare the practices in the two NICUs.

RESULTS

Patients in NICU A had smaller phlebotomy losses than those in NICU B. A lower percentage of the patients in NICU A (65% vs 87%) received transfusions, but they tended to receive a greater total volume per kg per patient (67 mL/kg vs 54.8 mL/kg). Transfusion timing differed between the NICUs; in NICU A only approximately one-half of their transfusions occurred in the first 2 weeks, whereas in NICU B almost 70% of the transfusions were given in this time period. Multivariate models showed that phlebotomy losses were significantly related to lower gestational age (GA) and higher SNAP. Hospitalization in NICU B resulted in 10.7 cc of additional losses relative to NICU A for a comparable GA and illness severity score. The volume of blood transfused per kilogram of body weight was a function of GA, SNAP, and hospital. Care practices in NICU A added an additional 19 cc of transfused volume in the first 14 days of life, and an additional 26 cc thereafter when adjusted for GA and SNAP. These differences in phlebotomy and transfusion were not associated with differences in the days of oxygen therapy or mechanical ventilation, the oxygen requirement at 28 days, the incidence of chronic lung disease, or the rate of growth by day 28.

CONCLUSIONS

We identified significant differences in phlebotomy and transfusion practices between two NICUs. We found no differences in short-term outcome, suggesting that the additional use of blood in one of the NICUs was discretionary rather than necessary. Our multivariate models can be used to characterize and quantify transfusion and phlebotomy practices. By predicting which patients are likely to require multiple transfusions, clinicians can target patients for erythropoietin therapy and identify those patients for whom donor exposure can be reduced by a unit of blood for multiple use. The models may help in monitoring changes in practice as they occur.

Collection and transfusion of blood in the United States, 1982-1988

Widespread concern about the safety of the national blood supply, particularly with respect to the human immunodeficiency virus (HIV), has reportedly affected the use of blood products to support patients. To examine these changes, we conducted national surveys of blood collection and transfusion in the United States in 1982, 1984, 1986, and 1987 and made a limited survey of these activities in 1988. Transfusions of whole blood and red cells reached a peak of 12.2 million units in 1986, then declined to 11.6 million units in 1987 and continued to decline in 1988. Transfusions of plasma declined from a peak of 2.3 million units in 1984 to 2.1 million units in 1987. Growth in the use of platelet transfusions (6.4 million units in 1987) also slowed; however, the proportion of platelets transfused as platelets from single donors grew from 11 percent in 1980 to 25 percent in 1987. Donations of autologous blood increased sharply, from less than 30,000 units in 1982 to 397,000 units in 1987, equivalent to 3 percent of the homologous-blood collections. The growth in collections of homologous blood slowed after 1982. The supply of homologous blood reached a peak of 13.4 million units in 1986 and did not grow between 1986 and 1988. These trends in red-cell, plasma, and platelet transfusions appear to have continued through 1988. We conclude that the unprecedented decline in transfusions of whole blood and red cells, coupled with the continued importation of packed red cells from Western Europe and the offsetting effect of autologous predeposits, forestalled serious shortages of blood that could have resulted from the decline in collections of homologous blood. We attribute these changes in blood collection and blood transfusion to the effects of the epidemic of HIV infection.