Reticulocyte counts and blood smears are commonly recommended to evaluate jaundice in newborns. To investigate the results and diagnostic yield of these tests, we reviewed a computerized database and medical records of term newborns who had reticulocyte counts (n = 799) or blood smears (n = 781) within the first week after birth at two hospitals. Nearly a threefold difference was noted in reticulocyte counts between the two hospitals (median 8.0% vs 2.8%; P < .0001), apparently due to differences in laboratory methods. Among the patients with "abnormal" reticulocyte counts or blood smears (n = 192), isoimmunization was diagnosed in 54, presumed hemolysis of unknown etiology in two, G6PD deficiency in one, and pyropoikilocytosis in one. We conclude that better standardization of reticulocyte counts is needed. When ordered as screening tests for hemolysis in jaundiced infants, reticulocyte counts and blood smears seldom lead to diagnoses of hemolysis other than isoimmunization.

OBJECTIVE:We evaluate the use of routinely gathered laboratory data to subclassify surgical and nonsurgical major diagnostic categories into groups homogeneous with respect to length of stay (LOS).DATA SOURCES AND STUDY SETTING:The source of data is the Combined Patient Experience database (COPE), created by merging data from computerized sources at the University of California San Francisco (UCSF) Medical Center and Stanford University Medical Center for a total sample size of 73,117 patient admissions.STUDY DESIGN:The study is cross-sectional and retrospective. All data were extracted from COPE consecutive admissions; the unit of analysis is an admission. The outcome variable LOS proxies hospital resource utilization for an inpatient stay. Nine (candidate) predictor variables were derived from seven lab tests (WBC, Na, K, C02, BUN, ALB, HCT) by recording the whole-stay minimum or maximum test result.DATA COLLECTION/EXTRACTION METHODS:Patient groups were formed by first assigning to major diagnostic categories (MDCs) all 73,117 admissions. Each MDC was then partitioned into medical and surgical subgroups (sub-MDCs). The 13 sub-MDCs selected for study define a study population of 32,599 patients that represents approximately 45 percent of inpatients. Within each of the 13 sub-MDCs, patients were randomly assigned to one of two data sets in a ratio of 2:1. The first set was used to create, the second to validate, three different LOS predictors. Predictive accuracies of individual DRG classes were compared with those of two alternative classification schemes, one formed by recursive partitioning (the sub-MDC) using only lab test results, the other by partitioning with both lab test results and individual DRGs.PRINCIPAL FINDINGS:For the eight largest sub-MDCs (81 percent of study population), individual DRGs explained 23 percent of the within sub-MDC variance in LOS, laboratory data classes explained 31 percent, and classes derived by considering individual DRGs and laboratory data explained 37 percent. (Each result is a weighted average R2. The average number of LOS classes into which the eight largest sub-MDCs were partitioned were 20, 10, and 10, respectively. Within six of the eight, partitioning on the basis of laboratory data alone explained more within sub-MDC variance than did partitioning into individual DRGs.CONCLUSIONS:Routine lab test data improve the accuracy of LOS prediction over that possible using DRG classes. We note that the improvements do not result from overfitting the data, since the numbers of LOS classes we use to predict LOS are considerably fewer than the numbers of individual DRGs.

With increasing availability of clinical data in machine-readable form, and decreasing cost of storing and manipulating that data, retrospective research using clinical databases has become more feasible. Nonetheless, much of the potential for clinical research using these data remains unrealized. Obstacles to clinical database research include difficulty accessing data, difficulty using retrospective data to draw valid inferences about medical tests and treatments, and a shortage of investigators trained and interested in using a clinical database to answer their questions. At the University of California, San Francisco, we have developed a Clinical Database Research Program (CDRP) to try to overcome these obstacles. The CDRP maintains a relational database of patient data obtained from diverse sources and a small staff dedicated to providing such data to researchers. The CDRP staff also provides support for design and analysis of studies using the database--the development of methods for such studies is our primary research interest. Finally, to increase the number of investigators using the database for research, we are integrating training in clinical epidemiology and clinical research methods into residency and fellowship training, and offering an elective in clinical database research for trainees who wish to undertake a specific project.

From a database of 93,077 in-patient admissions, patients assigned to catastrophic, very severe, moderately severe, and average 30-day mortality risk categories (as defined in Medicare Hospital Mortality Information, 1989 release, from the Health Care Financing Administration (HCFA] were selected for study. These admissions account for 30% of all admissions, but 70% of all deaths up to 1 year post admission. To determine whether laboratory information adds to the predictive power of the information used by HCFA, we compare the performance of 1 year survival predictors (Cox model) that use only diagnostic, demographic, and comorbidity information, with the performance of predictors that also include laboratory information. Using a separate set of patients not used for model definition, we find that laboratory data contain significant prognostic information independent of that already available in non-laboratory data. In HCFA's catastrophic disorders for example, non-laboratory information reduces the average risk of predicting a wrong outcome by 17% relative to considering only catastrophic group membership, and adding laboratory data reduces this risk by a further 21%. These improvements result primarily from considering the outcomes of a small set of routine laboratory tests (maximum BUN, AST, and WBC, and minimum CO2, hematocrit, and sodium).

Sir.—We wish to correct errors that we have discovered in our article that appeared in the March 1990 issue ofAJDC.1We used a computerized database of babies born at the University of California, San Francisco, Medical Center from 1980 to 1982 to determine the frequency and yield of bilirubin levels of at least 86 μmol/L (5 mg/dL) at less than 24 hours of age, 171 μmol/L (10 mg/dL) at less than 48 hours of age, and 223 μmol/L (13 mg/dL) thereafter. Unfortunately, we have determined that the time of birth in the database for those 2 years was not accurate, hence our estimate of the age at which bilirubin values were measured was sometimes incorrect. This led to considerable overestimation of the frequency of jaundice during the first 2 days of life and slight underestimation of the frequency of jaundice thereafter. The overall frequency of hyperbilirubinemia as

Eighty-eight patients entered into the British National Lymphoma Investigation with clinical stage I and II, grade I non-Hodgkin's lymphoma were treated initially with involved field radiotherapy alone. Eighty-one per cent presented with nodal disease. The duration of follow-up was 25–116 months, with a median of 54 months. Fifteen patients died of disease and the 5-year survival of the whole group was 83%. The complete response rate was dependent on the radiotherapy dose and was greater than 90% for doses of 3500 cGy and over. Most failures occurred at distant rather than adjacent sites, suggesting that extended field radiotherapy would not have affected the outcome. Second-line treatment induced complete remission in 66% of patients who relapsed. The prognosis was significantly worse in patients with intra-abdominal disease.

Nodular sclerosing (NS) Hodgkin's disease (HD) with extensive areas of lymphocyte depletion or with numerous anaplastic Hodgkin's cells, termed Grade II NS, is associated with a poor response to initial therapy, an increased relapse rate, and decreased survival when compared with other NS variants, termed Grade I NS. The histopathologic subdivision of NS HD into Grade I and Grade II is easy to perform and provides essential prognostic information that is independent of stage. Patients with Grade II NS HD may require more aggressive initial therapy if their survival is to be improved.

For 48 of the most common diagnosis-related groups (DRGs) at our hospital, we examined the ability of clinical laboratory tests, demographic data, and ICD-9-CM codes, which provide a measure of severity of illness, to predict patients' length of stay (LOS) more accurately than DRGs alone. For 10 of 20 medical DRGs and 13 of 23 surgical DRGs examined, we were able to increase the ability to predict LOS by at least 10 per cent. The laboratory tests that proved most predictive of LOS over all DRGs were the mean serum sodium, potassium, bicarbonate, and albumin. The system is data driven, objective, and flexible, thus ensuring its utility for the purpose of equitable reimbursement.

Systemic disturbances in Hodgkin's disease at presentation are not only manifested by 'B' symptoms (weight loss, fever, and night sweats), but are also mirrored in the peripheral blood as raised sedimentation rate, low haemoglobin, low albumin, and abnormal lymphocyte counts. Such systemic disturbance is more common than consideration of classical 'B' symptoms alone would suggest. In a series of 840 patients, 88% had some form of systemic disturbance on these criteria. Survival after treatment was found to be closely and inversely related to the degree of systemic disturbance present before treatment. Patients with no evidence of such disturbance had an almost 100% survival at 10 years. In the absence of 'B' symptoms the sedimentation rate was the most useful prognostic blood parameter, enabling about one third of the patients to be identified as having an excellent chance of survival, and identifying a further 12% as having a survival almost identical to that of patients with 'B' symptoms. The latter patients were those with a sedimentation rate of 60 mm/h or greater, and it is suggested that the term 'Systemic Symptoms' should be broadened to include a sedimentation rate of this magnitude. The degree of malignancy of the tumour, as reflected by histopathology, plays a dominant role in determining the amount of systemic disturbance in the host. However, the amount of disturbance varies amongst individual patients with the same histopathological subtype, reflecting either differences in the malignancy of the tumour within such subtypes, or differences in the constitution of the host.

Nodular sclerosis is the most commonly recognized histopathologic subtype of Hodgkin’s disease in many studies [1–5]. In the clinical trials of the British National Lymphoma Investigation (BNLI) [6], 75

A review of data from the British National Lymphoma Investigation (BNLI) studies of Hodgkin's disease (HD) done over the past 14 years shows (i) that systemic chemotherapy is appropriate for all clinical stages except I and IIA, and that MOPP (mustine, vincristine, procarbazine, and prednisone) courses are substantially more effective than MOP (the same without prednisone) but no better than the less toxic LOPP combinations (where chlorambucil replaces mustine); (ii) that local involved-field irradiation in stages I and IIA HD is as effective as wide-field in terms of both overall and recurrence-free survival; and (iii) that, histologically, nodular sclerosing HD can be divided into grades 1 and 2, the latter containing areas of lymphocyte depletion or numerous pleomorphic Hodgkin's cells. A multivariate analysis of factors influencing prognosis in clinical stages I and IIA disease shows that laparotomy has no significant effect but that age, sex, erythrocyte sedimentation (ESR), the presence or absence of mediastinal involvement and, especially, pathological grade are the most important factors influencing overall survival, while ESR, pathological grade, and stage of disease (I or II) correlate with recurrence-free time. A prognostic "survival" index was developed; an index of greater than 7.5 indicated a poor prognosis and that chemotherapy was perhaps more appropriate than local radiation. Laparotomy is no longer justified as a routine procedure in staging HD, although it may still be useful in special circumstances and in some research investigations.

This report reviews 85 patients entered into the British National Lymphoma Investigation with localised (clinical Stage 1 and 2) Grade 2 non-Hodgkin's lymphoma, who were treated initially with radiotherapy alone. Almost half of all patients presented with extranodal disease. The duration of follow-up was 20-106 months. There were 33 deaths due to non-Hodgkin's lymphoma. The complete local response rate was dependent on the radiotherapy dose and reached 100% for doses of 4500 cGy or more. Most first failures occurred at a distant nodal site or were due to the development of generalised disease. There was a significant difference in actuarial survival between Stage 1 and Stage 2 patients (P less than 0.005). The 5-year survivals were 78% and 40%, respectively. The site of presenting disease was also important. Stage 1 patients with nodal or ear, nose and throat (ENT) disease had an excellent 5-year survival of 84%, but Stage 2 patients with nodal or ENT disease had a 5-year survival of only 46%. As many of these Stage 2 patients rapidly developed disseminated disease, their survival might have been improved by treatment with chemotherapy before radiotherapy.

A histological review of 271 cases of nodular sclerosing Hodgkin's disease, patients presenting with clinical Stage I, II and III disease but not subjected to a staging laparotomy, has been undertaken. Cases were categorised according to the cytological appearances of the cellular nodules and the degree of sclerosis was examined. Cytological subtypes with extensive and easily recognised areas of lymphocyte depletion or numerous pleomorphic Hodgkin's cells were associated with a decreased survival and clinical stage did not appear to be a good indicator of prognosis in these patients. Pronounced nodal sclerosis was associated with a higher relative frequency of mediastinal disease and the lymphocyte-depleted cytological subtypes.

The presentation haemoglobin level was measured in 1103 patients with Hodgkin's disease. A reduced presentation haemoglobin level occurred with a higher relative frequency in patients with advanced disease, systemic (B) symptoms and aggressive histological subtypes. A reduced presentation haemoglobin was associated with a decreased survival.

Patients who were 50 years of age or older made up 21% of this group of 1500 patients. The survival of this age group was considerably less than that of younger patients. This difference in survival was present in both sexes, in all histological subtypes and clinical stages and in patients both with and without systemic 'B' symptoms. The overall difference in survival was only partly abolished by allowing for the reduced survival which occurs in all old people in the general population. Fewer of the older patients than the younger patients achieved complete remission. The relapse-free actuarial rate in patients who achieved complete remission appeared to be unaffected by age, being the same for the older patients as for the younger patients. However, in the event of relapse the survival of older patients was reduced.