A Prospective, Randomized, Open-Label Trial of Early versus Late Favipiravir Therapy in Hospitalized Patients with COVID-19.

Favipiravir is an oral broad-spectrum inhibitor of viral RNA-dependent RNA polymerase that is approved for treatment of influenza in Japan. We conducted a prospective, randomized, open-label, multicenter trial of favipiravir for the treatment of COVID-19 at 25 hospitals across Japan. Eligible patients were adolescents and adults admitted with COVID-19 who were asymptomatic or mildly ill and had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. Patients were randomly assigned at a 1:1 ratio to early or late favipiravir therapy (in the latter case, the same regimen starting on day 6 instead of day 1). The primary endpoint was viral clearance by day 6. The secondary endpoint was change in viral load by day 6. Exploratory endpoints included time to defervescence and resolution of symptoms. Eighty-nine patients were enrolled, of whom 69 were virologically evaluable. Viral clearance occurred within 6 days in 66.7% and 56.1% of the early and late treatment groups (adjusted hazard ratio [aHR], 1.42; 95% confidence interval [95% CI], 0.76 to 2.62). Of 30 patients who had a fever (≥37.5°C) on day 1, times to defervescence were 2.1 days and 3.2 days in the early and late treatment groups (aHR, 1.88; 95% CI, 0.81 to 4.35). During therapy, 84.1% developed transient hyperuricemia. Favipiravir did not significantly improve viral clearance as measured by reverse transcription-PCR (RT-PCR) by day 6 but was associated with numerical reduction in time to defervescence. Neither disease progression nor death occurred in any of the patients in either treatment group during the 28-day participation. (This study has been registered with the Japan Registry of Clinical Trials under number jRCTs041190120.).

Detecting Severe Incidents from Electronic Medical Records Using Machine Learning Methods.

The goal of this research was to design a solution to detect non-reported incidents, especially severe incidents. To achieve this goal, we proposed a method to process electronic medical records and automatically extract clinical notes describing severe incidents. To evaluate the proposed method, we implemented a system and used the system. The system successfully detected a non-reported incident to the safety management department.

How asymptomatic are early cancer patients of five organs based on registry data in Japan.

BACKGROUND: One reason for the low cancer screening rate in Japan is that people are not concerned about cancer if they do not have symptoms. METHODS: The authors retrospectively analyzed 18,405 cancer patients using hospital-based cancer registry data collected between 2007 and 2013 at the 13 hospitals of Shimane Prefecture, Japan. The symptomatic rates of five cancers (stomach, colorectal, lung, breast, and cervix) at each stage and the time of early diagnosis were investigated. The early detection rates of symptomatic and asymptomatic individuals were investigated. RESULTS: The percentages of symptomatic cases tended to increase with progressive stages. The odds ratio (OR) of stage IV compared with that of stage I was 12.23 for stomach, 7.21 for colorectal, 16.91 for lung, 10.30 for breast, and 51.62 for cervical cancer. The proportions of early symptomatic cases at the time of diagnosis were low. Compared with the percentage of early symptomatic cases of stomach cancer of 25.5%, the percentage of lung cancer was the lowest, at 8.2% (OR 0.26), and the percentage of breast cancer was the highest, at 30.2% (OR 1.26). The percentages of early symptomatic cases of colorectal and cervical cancer were 18.9% (OR 0.68) and 19.9% (OR 0.73), respectively. The early detection rates of the asymptomatic and symptomatic groups were 77.6 and 36.1%, respectively. CONCLUSION: Cancer registry data indicate that early cancers are asymptomatic, and once symptoms appear, treatment may not be effective. Policy makers should inform people of the necessity of cancer screening before they have symptoms.

Additional Medical Costs Due to Hospital-Acquired Falls.

OBJECTIVES: To explore the additional medical costs (AMCs) due to hospital-acquired falls (falls), as well as their impact on clinical services within hospitals under the nationally uniform universal health insurance system in Japan. METHODS: With the use of administrative profiling data based on accounting systems linked with the Japanese social insurance medical fee schedule, we analyzed data from 2 teaching hospitals: Shimane University Hospital (SUH) and St. Mary's Hospital (SMH). We extracted 588 fall cases from 4669 incident reports in SUH and 1168 fall cases from 7717 incident reports in SMH that potentially incurred AMCs. RESULTS: Additional medical costs were 364 ± 2129 USD for minor injuries and 4336 ± 3645 USD for major injuries at SUH (P < 0.001) and 114 ± 124 USD for minor injuries and 2267 ± 2811 USD for major injuries at SMH (P < 0.001). Among the clinical services provided, imaging services were the most frequently used, with 89.9% (n = 205) of 228 minor injuries at SUH and 86.7% (n = 339) of 391 minor injuries at SMH; imaging services were used in all major injury cases at both hospitals. Although the number of cases using additional procedure/surgery services was lower than those using imaging services at both hospitals, AMCs for procedure/surgery services accounted for the highest proportions of total AMCs in both hospitals. CONCLUSIONS: Although falls with minor injuries outnumbered falls with major injuries, fall-related AMCs for the latter were higher at both teaching hospitals because procedure/surgery services were required for cases with major injuries such as femoral neck and trochanteric fractures. The findings suggest that hospital administrators and policy makers have to take appropriate measures to prevent major injuries inpatients due to hospital-acquired falls.

Comparison of hemagglutination inhibition assay and enzyme immunoassay for determination of mumps and rubella immune status in health care personnel.

BACKGROUND: Screening tests are available to determine immunity to vaccine-preventable diseases, such as mumps and rubella. We aimed to define better assay for detecting immune status of health care personnel to vaccine-preventable diseases. METHODS: Mumps and rubella antibodies of health care personnel at Shimane University Hospital were examined by hemagglutination inhibition assay (HI), comparing with those by enzyme immunoassay (EIA). RESULTS: A total of 910 sera from health care personnel were tested. There was poor correlation between HI and EIA in detecting mumps antibodies with correlation coefficient values (r) = 0.190 (P < 0.001), but in rubella antibodies HI and EIA were relatively well correlated (r = 0.930, P < 0.001). Seropositivity rate of HI versus EIA was found to be 65.7 versus 93.2, and 89.5 versus 86.5% for mumps and rubella, respectively. As compared with EIA, HI identified sixfold larger seronegative subjects in mumps. Moreover, in mumps, 88.8% of seronegative subjects detected by HI were seropositive by EIA, while 3.7% of seropositive subjects detected by HI were seronegative by EIA. In rubella, 2.1% of seronegative subjects detected by HI were seropositive by EIA, and 1.7% of seropositive by HI was seronegative by EIA. CONCLUSION: Considerable difference between HI and EIA in determining immune status of health care personnel to mumps and rubella suggests beneficial use of EIA for the identification of accurate susceptible personnel who subsequently undergo an effective vaccination programs. Seroprevalence survey of health care personnel by using appropriate assay is essential for prevention and infection control strategies in health care settings.

Comparative analysis of a complement fixation assay and enzyme immunoassay to determine the seroprevalence of measles and varicella in a survey of healthcare workers.

OBJECTIVE: Seroprevalence surveys of healthcare workers for vaccine-preventable diseases, including measles and varicella, are essential for disease prevention and infection control programmes. The purpose of this study was to compare the complement fixation (CF) assay and an enzyme immunoassay (EIA) to determine the prevalence of immunoglobulin G antibodies directed against measles and varicella viruses in healthcare workers. METHODS: Antimeasles and antivaricella antibody titres were measured simultaneously in serum samples from healthcare workers employed at a Japanese university hospital, using the CF assay and an EIA. RESULTS: Serum samples were obtained from 898 healthcare workers. Seropositivity rates determined using the CF assay and EIA were 67.8% versus 94.0%, respectively, for measles, and 83.2% versus 97.6% for varicella. Compared with EIA, a nine- and 22-fold higher number of seronegative subjects was identified by the CF assay for measles and varicella, respectively. CONCLUSION: Differences between the CF assay and EIA in detecting seronegative or seropositive healthcare workers for measles and varicella suggest that undertaking a seroprevalence survey using an EIA, rather than a CF assay, would more accurately determine susceptibility to vaccine-preventable diseases, in healthcare settings.

High-sensitivity troponin T is a prognostic marker for patients with aortic stenosis after valve replacement surgery.

BACKGROUND: Aortic stenosis (AS) is recognized as a cause of sudden cardiac death. Recently, the measurement of high-sensitivity troponin T (hs-TnT) has become possible. Several studies have clarified that hs-TnT is a marker to indicate mortality of cardiovascular diseases. OBJECTIVES: To examine whether hs-TnT can be used as a prognostic marker to predict the operative outcome of AS. METHODS: We enrolled 60 patients with AS (mean age=68.7 ± 9.6 years, male/female=30/30). Cardiac catheterization and echocardiography were performed to evaluate the severity of AS. Aortic valve replacement surgery was performed in all patients. We defined major adverse cardiac events (MACE) as composite events of heart failure, fatal arrhythmia, and all causes of death. RESULTS: We followed up the patients for 922 ± 800 days. Mean left ventricular ejection fraction was 60.0 ± 1.8%. Mean aortic valve area was 0.61 ± 0.03 cm(2). MACE occurred in 11 patients (18%), including 5 sudden cardiac deaths. We divided the patients into three groups based on the percentile of the plasma levels of hs-TnT. Kaplan-Meier curve revealed a statistically significant difference in MACE rate among the groups (log-rank test, χ(2)=13.0, p=0.002). We conducted a Cox proportional hazard analysis with a model including age, sex, estimated glomerular filtration rate, and hs-TnT tertile as explanatory variables to predict MACE. We found that hs-TnT tertile to be a significant factor to predict MACE (hazard ratio: 3.71, p=0.03). CONCLUSIONS: hs-TnT can be a prognostic marker for patients with AS after valve replacement surgery.

Plasma endoglin as a marker to predict cardiovascular events in patients with chronic coronary artery diseases.

Recent clinical studies have revealed that the expression of endoglin, an accessory protein for the TGF-ß receptor, is increased in patients with atherosclerotic diseases. The plasma endoglin level is thought to represent endothelial activation, inflammation, and senescence. To clarify the significance of plasma endoglin in chronic coronary artery disease. Human umbilical vein endothelial cells (HUVECs) were cultured to examine changes in soluble endoglin (s-endoglin) levels caused by atherogenic stimulation in vitro. We studied 318 patients with stable coronary artery disease who underwent a successful percutaneous coronary intervention (PCI). Patients with acute coronary syndrome were excluded. Major adverse cardiovascular events (MACE) were congestive heart failure, acute myocardial infarction, stroke, and sudden cardiac death. All patients were followed-up to examine MACE after the procedure. We confirmed that the levels of s-endoglin was increased in the culture medium of HUVECs by senescence, tumor necrosis factor-α and hydrogen peroxide. In a clinical study, mean follow-up period was 1055 ± 612 days (49-2136 days) with 27 incidents of MACE (8.5%). We divided patients into three groups according to the plasma s-endoglin levels. Kaplan-Meier curves revealed that the highest endoglin group had a significantly higher MACE rate than the lowest endoglin group (log-rank test, p = 0.009). A Cox proportional hazards model showed that chronic kidney disease, left ventricular ejection fraction and s-endoglin level were significant factors to predict MACE. Plasma endoglin could be a marker to predict cardiovascular events in patients with chronic coronary artery disease after PCI.

Elevation of plasma granzyme B levels after acute myocardial infarction.

BACKGROUND: Apoptosis is reported to play an important role in left ventricular (LV) remodeling after acute myocardial infarction (AMI). Granzyme B is a member of the serine esterase family, which has an important role in cellular apoptosis and extracellular matrix degradation. METHODS AND RESULTS: Peripheral blood samples were obtained from 33 patients with a first-onset AMI treated by percutaneous coronary intervention (mean age: 61.4+/-8.7 years old) on days 1, 7 and 14 after onset. Plasma levels of tumor necrosis factor (TNF)-alpha, a soluble form of the Fas ligand (sFasL), and granzyme B were measured. TIMI grade 3 recanalization was accomplished in all patients within 12 h after onset. The LV end-diastolic volume index (LVEDVI) was calculated on day 1 and at 6 months after onset. Plasma levels of TNF-alpha, sFasL and granzyme B increased significantly on days 7 and 14 after onset of AMI. Stepwise multivariate regression analysis showed that the plasma granzyme B level on day 14 is a significant explanatory variable for changes in the LVEDVI. CONCLUSIONS: Plasma levels of granzyme B increased after AMI, which might be an important factor in the progression of late LV remodeling after AMI.

[A case of MPO-ANCA positive vasculitis associated with alveolar hemorrhage and progressive glomerulonephritis following propylthiouracil treatment, the interval was 6 years and 4 months].

The patient was a 62-year-old female. In June 1999, thiamazole (MMI) was orally administered under a diagnosis of hyperthyroidism. However, drug exanthema developed. In July, oral administration of propylthiouracil (PTU) was started. On October 20, 2005, palpitation and exertional dyspnea occurred. On November 1, bloody sputum was noted, and the patient consulted our hospital on November 8. In addition to severe anemia, chest X-ray and CT revealed diffuse infiltration in the bilateral lungs. The patient was admitted for detailed examination and treatment. After admission, the myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA) level was 390 EU, suggesting ANCA-associated angitis. PTU was discontinued, and steroid pulse therapy resulted in the disappearance of alveolar hemorrhage and hematuria. Transbronchial lung biopsy suggested alveolar hemorrhage, and kidney biopsy showed glomerular necrosis and interstitial infiltration of inflammatory cells, suggesting PTU-induced ANCA-associated angitis. Posttreatment with prednisolone at 30 mg/day gradually decreased the MPO-ANCA level. There has been no relapse during the 2-years follow-up.

Economic evaluations of maintaining patient safety systems in teaching hospitals.

OBJECTIVE: The aim of this study was to assess the status and the cost of hospital patient safety systems. METHODS: We conducted a national questionnaire survey of all the 1039 teaching hospitals in Japan. The study was constructed to evaluate the costs of the systems for patient safety focused on staff assignment, meetings and conferences, internal audit, staff education and training, incident reporting, infection surveillance, infectious disposal, management of medication use, clinical engineering, and patient counseling. RESULTS: The status to maintain patient safety systems might be at least as decent. The mean estimated total cost of systems for patient safety was US$ 20,449 (95% confidence interval [CI], 19,632-21,266) per 100 bed-months or US$ 8.52 (95% CI, 8.18-8.86) per inpatient-day. The ratio of costs to revenue was 1.68% (95% CI, 1.61-1.75). The annual necessary costs occurring in hospitals where the costs of patient safety were under the average level across all the 1032 teaching hospitals in Japan was US$ 259.7 million. CONCLUSIONS: Our results show that hospital-wide activities for patient safety pose significant costs to hospitals and national healthcare systems. Our data may provide financial information for designing and improving patient safety systems.

Lag time in an incident reporting system at a university hospital in Japan.

BACKGROUND: Delays and underreporting limit the success of hospital incident reporting systems, but little is known about the causes or implications of delayed reporting. SETTING AND METHODS: The authors examined 6880 incident reports filed by physicians and nurses for three years at a national university hospital in Japan and evaluated the lag time between each incident and the submission of a report. RESULTS: Although physicians and nurses reported nearly equal numbers of events resulting in major injury (32 v 31), physicians reported far fewer minor incidents (430 v 6387) and far fewer incidents overall (462 v 6418). In univariate analyses, lag time was significantly longer for physicians than nurses (3.79 v 2.20 days; p<0.001). In multivariate analysis, physicians had adjusted reporting lag time 75% longer than nurses (p<0.001) and lag time for major injuries was 18% shorter than for minor injuries (p = 0.011). Adjusted lag time in 2002 and 2004 were 34% longer than in 2003 (p<0.001). CONCLUSIONS: Physicians report fewer incidents than nurses and take longer to report them. Quantitative evaluation of lag time may facilitate improvements in incident reporting systems by distinguishing institutional obstacles to physician reporting from physicians' lesser willingness to report.

[A patient who sufferred pulmonary tuberculosis with syndrome of inappropriate secretion of antidiuretic hormone, after radiotherapy for pulmonary adenocarcinoma].

A 62-year-old man presented in June 2006 with right thoracic pain, cough, and weight loss, which had persisted for 3 months. Chest X-ray showed a mass-like shadow in the right pulmonary apex, suggesting a stage IIIb adenocarcinoma which was confirmed by biopsy. We gave a total radiation dose of 60 Gy, after this which general malaise and weakness were noted. The results of endocrinological examinations suggested syndrome of inappropriate antidiuretic hormone secretion (SIADH). Thoracic CT showed ground-glass opacity (GGO) in both lungs, and we could not rule out pulmonary tuberculosis. A sputum was positive for acid-fast stain and PCR-Tb, suggesting that SIADH was associated with pulmonary tuberculosis. Water restriction, i.v. physiological saline, and antituberculosis therapy relieved hyponatremia and the symptoms.

[Cholesterol pericarditis identified by increased cardiothoracic ratio on chest radiography: a case report].

A 72-year-old man with no symptoms was admitted to our hospital to investigate increased cardiothoracic ratio on chest radiography. There were no specific physical findings but the cardiac sound was weak. Electrocardiography showed low voltage in all leads. Thyroid function was within normal limits. Echocardiography revealed massive pericardial effusion. Pericardiocentesis was performed, and 1,800ml of gold paint-like opaque fluid was drained. Microscopic examination revealed cholesterol crystals, so the diagnosis was cholesterol pericarditis. Cytologic examination revealed no malignant cells, and no bacteria was cultured. Mycobacterium tuberculosis was not amplified using the polymerase chain reaction method of pericardial fluid. Further analysis showed reduction of apo-B in the pericardial fluid, suggesting involvement in the precipitation of cholesterol.

[A couple suffering acute respiratory illness due to waterproofing spray exposure].

The patients were a 28-year-old man and a his 27-year-old wife. The husband smoked a cigarette immediately after using a waterproofing spray, and developed fever, cough, and dyspnea 15 min later. The wife had nausea 2 hours later. Nine hours later, the husband visited a local clinic, and was referred to our hospital because of hypoxemia. In addition, chest CT showed ill-defined areas of increased density, predominantly in the bilateral upper lung fields, with interlobular septal thickening, and he was hospitalized. Although the wife was asymptomatic at the time of examination, she had chest CT findings similar to those of her husband, and was also hospitalized. After admission, the husband received steroid pulse therapy and oxygen inhalation for his symptoms and hypoxemia, with return of arterial blood gas analysis results to normal on the third day. The wife had no symptoms or hypoxemia during her hospital stay. Their chest CT findings improved on the seventh day after admission, and they were discharged. Thus, it appears that the couple suffered from acute respiratory illness due to waterproofing spray exposure, and probably heat degradation products from cigarette smoking caused the husband to have severe symptoms.

Impact of treatment policies on patient outcomes and resource utilization in acute cholecystitis in Japanese hospitals.

BACKGROUND: Although currently available evidence predominantly recommends early laparoscopic cholecystectomy (LC) for the treatment of acute cholecystitis, this strategy has not been widely adopted in Japan. Herein, we describe a hospital-based study of patients with acute cholecystitis in 9 Japanese teaching hospitals in order to evaluate the impact of different institutional strategies in treating acute cholecystitis on overall patient outcomes and medical resource utilization. METHODS: From an administrative database and chart review, we identified 228 patients diagnosed with acute cholecystitis who underwent cholecystectomy between April 2001 and June 2003. In order to examine the relationship between hospitals' propensity to perform LC and patient outcomes and/or medical resource utilization, we divided the hospitals into three groups according to the observed to expected ratio of performing LC (LC propensity), and compared the postoperative complication rate, length of hospitalization (LOS), and medical charges. RESULTS: No hospital adopted the policy of early surgery, and the mean overall LOS among the subjects was 30.9 days. The use of laparoscopic surgery varied widely across the hospitals; the adjusted rates of LC to total cholecystectomies ranged from 9.5% to 77%. Although intra-operative complication rate was significantly higher among patients whom LC was initially attempted when compared to those whom OC was initially attempted (9.7% vs. 0%), there was no significant association between LC propensity and postoperative complication rates. Although the postoperative time to oral intake and postoperative LOS was significantly shorter in hospitals with high use of LC, the overall LOS did not differ among hospital groups with different LC propensities. Medical charges were not associated with LC propensity. CONCLUSION: Under the prevailing policy of delayed surgery, in terms of the postoperative complication rate and medical resource utilization, our study did not show the superiority of LC in treating acute cholecystitis patients. The timing of surgery and discharge was mainly determined by the institutional policy in Japan, rather than by the clinical course of the patient; however, considering the substantially less postoperative pain and shorter recovery time of LC compared to OC, LC should be actively applied for the treatment of acute cholecystitis. If the policy of early surgery were universally applied, the advantage of LC over OC may be more clearly demonstrated.

[A case of adult idiopathic chylothorax with transudative ascites].

A 70-year-old woman presented at a local clinic because of shortness of breath. Since she was found to have pleural effusion, she was referred to our hospital for further evaluation. She had no history of trauma or surgery. Pleural effusion examination revealed a milky-white, chylous, odorless fluid with increased triglycerides. Further evaluation led to a diagnosis of idiopathic chylothorax. Althought she was found to have transudative ascites, abdominal ultrasonography and computed tomography revealed no significant findings including cirrhosis of the liver. As a result of intravenous hyperalimentation with fasting, the chylous pleural fluid became serous and decreased. Ascites disappeared simultaneously, suggesting a possible relationship between the chylothorax and transudative ascites.

Profiling hospital performance of laparoscopic cholecystectomy based on the administrative data of four teaching hospitals in Japan.

Over the last decade in Japan, laparoscopic cholecystectomy (LC) has replaced traditional open cholecystectomy as the standard of elective surgery for cholelithiasis. The laparoscopic approach has a clinical course relatively easier to standardize among the different types of intraabdominal surgery. However, significant practice variation is suspected in Japan, but there has been little demonstration or discussion based on empirical data. Through the analysis of 1589 elective LC cases from four leading teaching hospitals in Japan between 1996 and 2000, this study aims to demonstrate the surgical variations and to investigate their determinants regarding the length of hospital stay and the health care charge. Substantially and significantly large variation existed among the hospitals in terms of the length of hospital stay and the total health care charge, even after the differences in patient factors were adjusted. Particularly, the combined drug and exam charge per day was strikingly different among the four hospitals, which indicated that the daily process also varied widely, as did the total course of inpatient care. In addition, intra-hospital variation was also remained very large even after adjusting for all the potential correlates studied. This study alarmingly points out great room for improvement in the efficiency of health care resource use and potentially in the quality of care through standardization of LC. It has serious implications for the national policy and individual providers under the on-going health care reforms directed toward higher efficiency and quality.

Practice variation in perioperative antibiotic use in Japan.

OBJECTIVE: Under the fee-for-service system, the overuse and misuse of perioperative antibiotics have become serious concerns in Japan. The objective of the present study is to investigate practice variations of perioperative antimicrobial prophylaxis between and within hospitals, and to identify any opportunities for improvement. METHODS: We polled 319 surgeons in six specialties employed by 11 teaching hospitals in Japan. We developed questionnaires with vignettes, asking physicians about their practice of antimicrobial prophylaxis in six surgical procedures (gastrectomy, hysterectomy, cataract surgery, clipping of cerebral aneurysm, hip fracture surgery, and coronary artery bypass graft) and utilization of institutional clinical pathways. RESULTS: Average durations of prophylaxis varied by procedure, from 1.6 days for cataract surgery to 5.8 days for clipping surgery. Variation was also observed between institutions for the same procedure, e.g. institutional averages for the duration of prophylaxis for gastrectomy ranged from 2.3 to 7 days. Large intra-institutional variation in prophylaxis duration and inconsistent use of clinical pathways were observed in the cases of gastrectomy, hip fracture surgery, and clipping surgery. At one hospital, 20% of physicians performing gastrectomy indicated the use of an institutional clinical pathway, and prophylaxis duration ranged from 3 to 6 days. For cataract surgery and hysterectomy, clinical pathways were universally applied and intra-institutional practice variation was small, yet prophylaxis duration varied widely between hospitals and third-generation cephalosporins were used extensively. Average length of prophylaxis for hysterectomy ranged from 1.8 to 6 days and 43% of respondents prescribed third-generation cephalosporins. CONCLUSIONS: In Japan, perioperative antimicrobial prophylaxis lacks standardization. Efforts to strengthen an evidence-based approach to antimicrobial prophylaxis need to be made a priority at both the national and institutional levels.

Association of hospital resource use with comorbidity status and patient age among hip fracture patients in Japan.

OBJECTIVES: This study examined the association of resource use with comorbidity status and patient age among hip fracture patients who underwent surgical treatment. DESIGN: We used a database from the Voluntary Hospitals of Japan Quality Indicator Project that involved 10 privately owned leading teaching hospitals in Japan. SETTING: Four of these hospitals in Japan. PARTICIPANTS: We selected 778 operable hip fracture patients aged 65 or older who were admitted to these hospitals between January 1996 and August 2000 (mean age: 80.3 +/- 7.3 years). MEASUREMENTS: A linear mixed model was performed to identify factors associated with the resource use, such as total length of stay (LOS), LOS before surgery, LOS after surgery, total hospital charges, charges for diagnostic examinations, charges for surgery, and length of theater time, among operable hip fracture patients. RESULTS: The mean LOS was 45.9 days, and the mean total hospital charges were US dollars 14,495.0. Results from linear mixed models revealed that higher age was significantly associated with shorter length of theater time (P < 0.01), and that the presence of comorbidity among hip fracture patients was significantly associated with longer total LOS (P < 0.01), longer LOS after surgery (P < 0.001), higher charges for diagnostic examinations (P < 0.001), and shorter length of theater time (P < 0.01). CONCLUSION: These results suggest that the presence of comorbidity among operable hip fracture patients requires greater resource use during their hospital stay, but higher age is not significantly associated with greater resource use at all.