When and how to split the follow-up time in the analysis of epidemiological or clinical studies with follow-ups.

In epidemiological or clinical studies with follow-ups, data tables generated and processed for statistical analysis are often of the "wide-format" type-consisting of one row per individual. However, depending on the situation and purpose of the study, they may need to be transformed into the "long-format" type-which allows for multiple rows per individual. This tutorial clarifies the typical situations wherein researchers are recommended to split follow-up times to generate long-format data tables. In such applications, the major analytical aims consist of (i) estimating the outcome incidence rates or their ratios between ≥ 2 groups, according to specific follow-up time periods; (ii) examining the interaction between the exposure status and follow-up time to assess the proportional hazards assumption in Cox models; (iii) dealing with time-varying exposures for descriptive or predictive purposes; (iv) estimating the causal effects of time-varying exposures while adjusting for time-varying confounders that may be affected by past exposures; and (v) comparing different time periods within the same individual in self-controlled case series analyses. This tutorial also discusses how to split follow-up times according to their purposes in practical settings, providing example codes in Stata, R, and SAS.

Effect of periodontal therapy on glycaemic control in type 2 diabetes.

AIM: This study aimed to elucidate the impact of periodontal therapy on glycaemic control in individuals with type 2 diabetes and various baseline blood glucose levels using a large-scale claims database from Japan. MATERIALS AND METHODS: Using the JMDC Claims Database, we identified individuals with type 2 diabetes who underwent health check-ups in the fiscal years 2018 or 2019 and were followed up until the next year's health check-up. We conducted a weighted cohort analysis using stabilized inverse probability weights for treatment and censoring to estimate the effect of periodontal therapy on changes in haemoglobin A1c levels within a year. Analysis was done for different baseline haemoglobin A1c categories: 6.5%-6.9%, 7.0%-7.9% and ≥8.0%. RESULTS: Of the 4279 insured persons included in the study, 957 received periodontal therapy. Overall, there was a tendency towards improved glycaemic control among those who received periodontal therapy. Participants with baseline haemoglobin A1c levels of 7.0%-7.9% who received periodontal therapy exhibited significantly better glycaemic control compared with those without dental visits (difference; -0.094 [95% confidence interval: -0.181 to -0.007]). CONCLUSIONS: Periodontal therapy may improve glycaemic control in individuals with diabetes, especially in those with haemoglobin A1c levels ≥7.0%.

Associations between school-based fluoride mouth-rinse program, medical-dental expense subsidy policy, and children's oral health in Japan: an ecological study.

BACKGROUND: Dental caries are a common non-communicable disease among children. As a public health measure at the prefectural level, school-based fluoride mouth-rinse (S-FMR) program, medical/dental expense subsidy policies, and other factors may reduce the incidence of dental caries and tooth loss. Prefectures focusing on promoting oral health policies may promote both, but the interaction effect of implementing both subsidy policies and S-FMR at the prefectural level on caries prevention has not yet been examined. METHODS: We conducted an ecological study using two-wave panel data, prefecture-level aggregated data in Japan for 2016 and 2018. Coefficient and 95% confidence intervals (CI) were calculated for the dependent variables for oral health using mixed-effects linear regression analysis adjusted for possible confounders. Two dependent variables were used; the standardized claim ratio (SCR) of deciduous tooth extraction and 12-year-olds' decayed, missing, or filled permanent teeth (DMFT). Four independent variables were S-FMR, the SCR of dental sealants, prefectural income per person, and subsidy policy in three models: co-payment until children enter elementary school (n = 23), no co-payment until children enter elementary school (n = 7), and co-payment continuing beyond elementary school (n = 17). The effects of six interaction terms, each representing a unique pairing from the four independent variables, were individually calculated. RESULTS: S-FMR was negatively associated with the SCR of deciduous tooth extractions and DMFT (coefficient = -0.11, 95% CI -0.20; -0.01 and coefficient = -0.003, 95% CI -0.005; -0.001, respectively). No co-payment until children enter elementary school was positively associated with the SCR of deciduous tooth extraction compared to co-payment until children enter elementary school(coefficient = 11.42, 95% CI 3.29; 19.55). SCR of dental sealants was positively associated with the SCR of deciduous tooth extractions (coefficient = 0.12, 95% CI 0.06; 0.19) but negatively associated with DMFT (coefficient = -0.001, 95% CI -0.003; -0.0001). Per capita prefectural income was positively associated with the SCR of deciduous tooth extractions(coefficient = 0.01, 95% CI 0.001; 0.02). No interaction was found between S-FMR and the subsidy policy at both outcomes. CONCLUSION: High S-FMR utilization and no co-payment until children enter elementary school were associated with fewer deciduous tooth extractions. Also, S-FMR and dental sealant were associated with decreased DMFT.

Incidence of Sympathetic Ophthalmia after Inciting Events: A National Database Study in Japan.

PURPOSE: To analyze the incidence of sympathetic ophthalmia (SO) after inciting events (eye trauma or intraocular surgery). DESIGN: Retrospective cohort study. PARTICIPANTS: Patients experiencing inciting events between 2012 and 2019. Onset of SO was defined as the first date of SO diagnosis. METHODS: Using a nationwide administrative claims database in Japan, we calculated the cumulative incidence of SO after inciting events stratified by sex, 10-year age groups, and a categorical variable of primary or repeated, reflecting the history of inciting events in the past year (no inciting events, inciting events without trauma, or inciting events with trauma) using the Kaplan-Meier approach. We also estimated the adjusted hazard ratio (aHR) by Cox regression. We then restricted the population to those with only 1 inciting event during the observation period to investigate the pure effect of each inciting event. MAIN OUTCOME MEASURES: Cumulative incidence of SO over 60 months. RESULTS: A total of 888 041 inciting events (704 717 patients) were eligible. The total number of SO cases was 263, and the cumulative incidence of SO was 0.044% over 60 months. Female sex was not associated with onset of SO (aHR, 1.01; 95% confidence interval [CI], 0.79-1.29; P = 0.95). The group 40 to 49 years of age showed the highest incidence of 0.104% among the age groups (aHR vs. ≥80 years of age group [0.041%], 2.44 [95% CI, 1.56-3.80]; P < 0.001). Repeated inciting events with and without trauma showed higher incidences of SO (0.469% and 0.072%, respectively) than primary inciting events (0.036%) (aHR 11.68 [7.74-17.64] and 2.21 [95% CI, 1.59-3.07], respectively); P < 0.001 and P < 0.001, respectively). The incidence of SO after vitrectomy was much lower than after trauma (0.016% vs. 0.073%), and the incidence after scleral buckling was even lower. CONCLUSIONS: The cumulative incidence of SO over 60 months was estimated to be 0.044% at minimum. Repeated inciting events, especially those with trauma, increased the risk of SO developing. Trauma was 4 to 5 times as likely to induce SO than vitrectomy. The present findings will be valuable for counseling patients about the risks of SO after trauma and before performing intraocular surgeries.

Trends in prophylactic antibiotic use for tooth extraction from 2015 to 2018 in Japan: An analysis using a health insurance claims database.

INTRODUCTION: To describe patterns in antibiotic prophylaxis for tooth extraction following the 2016 Japanese National Action Plan on Antimicrobial Resistance. METHODS: Using a health insurance claims database, we retrospectively identified tooth extraction visits by patients aged ≥18 years from September 2015 to August 2018 and classified patients as undergoing extraction of a fully impacted or horizontally impacted mandibular wisdom tooth, being at risk of infective endocarditis or surgical site infection, or being at low risk. Antibiotic use and type of antibiotics prescribed on the day of tooth extraction were evaluated across the study period, with stratification by tooth extraction category and facility type (hospital or dental clinic). RESULTS: We identified 662,435 patients with tooth extraction. The mean age was 42.7 years, and 57% were male. Twelve percent underwent wisdom tooth extraction, 32% were high risk, and 10% visited hospitals. The proportion of antibiotic use was 83% overall and 82% among low-risk patients. This proportion remained similar throughout the study period. A shift from third-generation cephalosporins to amoxicillin was observed from 2015 to 2018: the proportion prescribed third-generation cephalosporins decreased from 58% to 34% in hospitals and from 57% to 56% in clinics, and the proportion prescribed amoxicillin increased from 16% to 37% in hospitals and from 6% to 10% in clinics. CONCLUSIONS: The pattern of prophylactic antibiotic use for tooth extraction gradually changed after the initiation of the National Action Plan. Further efforts are required to reduce potentially inappropriate prescriptions for low-risk patients, especially in dental clinics.

Amoxicillin vs third-generation cephalosporin for infection prophylaxis after third molar extraction.

OBJECTIVES: Although amoxicillin is the first-line prophylactic drug for impacted mandibular third molar extraction, third-generation cephalosporins are widely prescribed in Japan. The lack of real-world evidence may be one reason for this inappropriate use. We evaluated differences in the incidence of surgical site infection between amoxicillin and third-generation cephalosporins for impacted mandibular third molar extraction. METHODS: Using the JMDC Claims Database, we identified dental visits with fully or horizontally impacted mandibular third molar extraction from April 2015 to March 2020. One-to-one propensity-score matching was conducted between amoxicillin and third-generation cephalosporin groups. The incidence of surgical site infection following extraction was compared in the matched pairs using McNemar's test. RESULTS: We identified 109,266 dental visits, including 39,514 (36.2%) patients who received amoxicillin and 69,752 (63.8%) patients who received third-generation cephalosporins. In the 39,514 matched pairs, the incidence of surgical site infection was 3.5% (n = 1399) for amoxicillin group and 3.7% (n = 1467) for third-generation cephalosporin group (p = 0.003). CONCLUSIONS: Amoxicillin was associated with a lower incidence of surgical site infection after impacted mandibular third molar extraction compared with third-generation cephalosporins. This result supports current guidelines and strengthens the importance of disseminating and implementing antimicrobial resistance control in dentistry.

Prevalence, Incidence Rate, and Risk Factors of Medication-Related Osteonecrosis of the Jaw in Patients With Osteoporosis and Cancer: A Nationwide Population-Based Study in Japan.

PURPOSE: Medication-related osteonecrosis of the jaw (MRONJ) is a rare but severe adverse event of antiresorptive agents. However, the precise prevalence and factors associated with the development of MRONJ remain unknown. The present study was performed to describe the prevalence, incidence rate, and risk factors of developing MRONJ. METHODS: We conducted a population-based retrospective cohort study using the National Database of Health Insurance, an administrative claims database of all patients in Japan. We identified patients who newly began using antiresorptive drugs from April 2015 to December 2018. The primary outcome was the development of MRONJ. We calculated the prevalence and incidence rate of MRONJ and performed a time-dependent Cox proportional hazard regression analysis to examine risk factors for developing MRONJ. RESULTS: We identified 2,819,310 patients who newly used antiresorptive drugs during the study period. Of these patients, 2,664,104 (94.5%) had osteoporosis and 155,206 had cancer. Among the patients with osteoporosis, 1,603 (0.06%) developed MRONJ; the incidence rate was 22.9 per 100,000 person-years. Among the patients with cancer, 2,274 (1.47%) developed MRONJ; the incidence rate was 1,231.7 per 100,000 person-years. The occurrence of MRONJ was associated with poor oral conditions (including tooth extraction), age, male sex, drug type, concomitant drug use, comorbidities, cancer type, and geographic location. CONCLUSIONS: The overall prevalence and incidence rate were low, but they were still higher than those in previous studies. Poor oral conditions were more closely related to the development of MRONJ than other factors. These findings suggest that improving poor oral hygiene may be essential to prevent MRONJ.

Association of marital status and access to dental care among the Japanese population: a cross-sectional study.

BACKGROUND: Health disparities according to marital status have been reported worldwide. Although spouses provide an important social network that influences heath behaviors, limited studies have examined the association between marital status and access to dental care. Therefore, this study aimed to analyze the association between marital status and access to dental care. METHODS: A secondary analysis of the 2013 Comprehensive Survey of Living Conditions in Japan which is a national survey, was performed in this study. Out of 367,766 respondents, 4111 respondents, aged over 40 years who selected oral symptoms as their most concerning subjective symptom were recruited as participants. The independent variable of interest was marital status-married or non-married (single, divorced, widowed); and the dependent variable was access to dental care. We performed Poisson regression analyses stratified by sex with adjustment for age, educational status, employment, equivalent household expenditure, and smoking habits. RESULTS: Among respondents who reported oral symptoms, 3024 were married, and 1087 were non-married. Further, 29.4% and 40.4% of married and non-married men, respectively, did not receive dental treatment for their symptoms. Meanwhile, 27.5% and 25.0% of married and non-married women, respectively, did not receive dental treatment for their symptoms. The prevalence ratio for not receiving dental treatment was significantly higher among non-married men (prevalence ratio: 1.33; 95% confidence interval: 1.14-1.56) than among married men. However, no significant association was observed among women. CONCLUSIONS: Non-married men were highly unlikely to receive dental treatment than married men, while no significant association was observed among women. The results implicate the importance of implementing a public dental health policy for protecting the dental health of non-married individuals.

Risk of drug-induced interstitial lung disease in hospitalised patients: a nested case-control study.

INTRODUCTION: Information on drug-induced interstitial lung disease (DILD) is limited due to its low incidence. This study investigated the frequencies of drug categories with potential risk in patients developing DILD during hospitalisation and analysed the risk of developing DILD associated with each of these drugs. METHODS: Using a Japanese national inpatient database, we identified patients without interstitial pneumonia on admission who developed DILD and required corticosteroid therapy during hospitalisation from July 2010 to March 2016. We conducted a nested case-control study; four controls from the entire non-DILD patient cohort were matched to each DILD case on age, sex, main diagnosis, admission year and hospital. We defined 42 classified categories of drugs with 216 generic names as drugs with potential risk of DILD, and we identified the use of these drugs during hospitalisation for each patient. We analysed the association between each drug category and DILD development using conditional logistic regression analyses. RESULTS: We retrospectively identified 2342 patients who developed DILD. After one-to-four case-control matching, 1541 case patients were matched with 5677 control patients. Six drug categories were significantly associated with the increased occurrence of DILD. These included epidermal growth factor receptor inhibitors (OR: 16.84, 95% CI 9.32 to 30.41) and class III antiarrhythmic drugs (OR: 7.01, 95% CI 3.86 to 12.73). Statins were associated with reduced risk of DILD (OR: 0.68, 95% CI 0.50 to 0.92). CONCLUSIONS: We demonstrated significant associations between various drug categories and DILD. Our findings provide useful information on drug categories with potential risk to help physicians prevent and treat DILD.

The association of remdesivir and in-hospital outcomes for COVID-19 patients treated with steroids.

BACKGROUND: Remdesivir has been shown to decrease SARS-CoV-2 viral loads and the duration of COVID-19 symptoms. However, current evidence regarding the association between remdesivir and in-hospital mortality for patients with COVID-19 steroid treatments is limited. We aimed to investigate whether remdesivir reduces in-hospital mortality among patients with COVID-19 treated with steroids. METHODS: In this retrospective multicentre study, we reviewed the medical records of 3372 patients discharged between 1 March 2020 and 30 March 2021, with laboratory confirmed COVID-19 in the Mount Sinai Health System and treated with steroids. We evaluated the effect of remdesivir on the outcomes using propensity score analyses. Subgroup analyses were conducted by stratification of patients by endotracheal intubation and COVID-19 antibody status. Acute kidney injury (AKI) was defined as an absolute serum creatinine increase of 0.3 mg/dL or a relative increase of 50%. RESULTS: Of the 3372 eligible patients, 1336 (39.6%) received remdesivir. After 1:1 propensity score matching (N = 999 pairs), in-hospital mortality was similar between those with and without remdesivir (21.4% versus 21.6%, respectively, P = 0.96). Remdesivir was not significantly associated with in-hospital mortality regardless of endotracheal intubation or COVID-19 antibody status. However, there was a signal that remdesivir was associated with a reduced risk of AKI in the propensity matched analysis (17.5% versus 23.4%, respectively, P = 0.001). CONCLUSIONS: Remdesivir was not associated with reduced risk of in-hospital mortality in patients with COVID-19 treated with steroids but potentially associated with decreased risk of AKI. These findings should be confirmed in prospective studies focusing on COVID-19 patients treated with steroids.

Effect of tranexamic acid in patients with colonic diverticular bleeding: A nationwide inpatient database study.

BACKGROUND AND AIM: The effect of tranexamic acid (TXA) remains unknown in patients with colonic diverticular bleeding, which is one of the most common causes of lower gastrointestinal bleeding. We investigated the efficacy of TXA for patients with colonic diverticular bleeding. METHODS: We performed a nationwide observational study using the Japanese Diagnosis Procedure Combination database and identified patients who were admitted for diverticular bleeding from 2010 to 2018. Patients who received TXA on the day of admission comprised the TXA group, and the remaining patients comprised the control group. The primary outcome was in-hospital mortality. Secondary outcomes included severe bleeding, blood transfusion within 7 days of admission, length of stay, and hospitalization costs. Propensity score matching was performed to compare outcomes between the two groups. RESULTS: Overall, 78 291 patients met our eligibility criteria, and 30 526 matched pairs were created by one-to-one propensity score matching. After matching, there was no significant difference in in-hospital mortality between the two groups (odds ratio [OR], 1.07; 95% confidence interval [CI], 0.88-1.30); however, TXA administration was associated with significantly lower proportions of severe bleeding events (OR, 0.93; 95% CI, 0.89-0.99), blood transfusions (OR, 0.88; 95% CI, 0.84-0.92), shorter length of stay (difference, -0.23 days; 95% CI, -0.01 to -0.44 days), and lower total hospitalization costs (difference, -$233; 95% CI, -$153 to -$314). CONCLUSIONS: Although TXA was not significantly associated with lower in-hospital mortality, it may reduce severe bleeding, blood transfusions, length of stay, and hospitalization costs.

Validity of diagnoses and procedures in Japanese dental claims data.

BACKGROUND: Dental claims data have been used for epidemiological studies without establishing the validity of the recorded diagnoses or procedures. The present study aimed to examine the accuracy of diagnoses, procedures, operation time, and the number of teeth recorded in dental claims data. METHODS: We reviewed the charts of 200 patients who visited and 100 patients who were hospitalized in the Department of General Dentistry, Orthodontics, and Oral and Maxillofacial Surgery in an academic hospital between August 2012 and December 2017. The sensitivity and specificity of the dental claims data for five diseases and 15 procedures were evaluated. We assessed the difference in the number of teeth and duration of general anesthesia between claims data and chart reviews. RESULTS: Sensitivity was more than 86% for six out of seven diagnoses except for pericoronitis (67%). Specificity ranged from 72% (periodontal disease) to 100% (oral cancer for inpatient). The sensitivity of procedures ranged from 10% (scaling for inpatient) to 100%, and the specificity ranged from 6% (food intake on the day of the surgery) to 100%. The mean (standard deviation [SD]) number of teeth in the chart review was 22.6 (6.8), and in the dental claims was 21.6 (8.6). The mean (SD) operation time was 171.2 (120.3) minutes, while the duration of general anesthesia was 270.9 (171.3) minutes. CONCLUSIONS: The present study is the first study to validate dental claims data, and indicates the extent of usefulness of each diagnosis and procedure for future dental research using administrative data.

Outcomes of endoscopic sinus surgery for sinusitis-induced intracranial abscess in patients undergoing neurosurgery.

OBJECTIVE: Although sinusitis-induced intracranial complications rarely occur in the current era of antibiotics, they can induce neurological symptoms or death. The authors of this study investigated the association between endoscopic sinus surgery (ESS) and outcomes in patients who had undergone neurosurgical procedures for sinusitis-induced intracranial abscess. METHODS: The authors obtained data on patients with sinusitis-induced intracranial abscess from the Japanese Diagnosis Procedure Combination inpatient data for the period from 2010 to 2017. They excluded patients with fungal sinusitis, orbital complications, immunodeficiency, and malignant disease. They also excluded patients who had received antifungal agents, chemotherapy, immunosuppressants, and antidiabetic drugs. Eligible patients were divided into those with and those without neurosurgical procedures. Propensity score-adjusted regression analyses were performed to examine the association between ESS within the same hospitalization and outcomes (mortality, blood transfusion, readmission, revision neurosurgery, and length of stay). RESULTS: Of the 552 potentially eligible patients, 255 were treated with neurosurgical procedures, including 104 who underwent ESS within the same hospitalization and 151 who did not. ESS was not significantly associated with mortality (OR 0.54, 95% CI 0.05-5.81, p = 0.61), blood transfusion (OR 1.95, 95% CI 0.84-4.51, p = 0.12), readmission (OR 0.86, 95% CI 0.34-2.16, p = 0.75), revision neurosurgery (OR 0.65, 95% CI 0.24-1.74, p = 0.39), or length of stay (percent difference -10.8%, 95% CI -24.4% to 5.1%, p = 0.18). CONCLUSIONS: The present study suggests that ESS may not have significant benefits with respect to reducing mortality, blood transfusion, readmission, revision neurosurgery, or length of stay.

Tranexamic acid and post-tonsillectomy hemorrhage: propensity score and instrumental variable analyses.

PURPOSE: Although post-tonsillectomy hemorrhage occurs rarely, it can be life-threatening. Previous studies showed that tranexamic acid (TXA) had insignificant association with the rate of post-tonsillectomy hemorrhage, but those findings were limited by small sample sizes. The purpose of this study was to examine the effectiveness of TXA in preventing post-tonsillectomy hemorrhage using nationwide database. METHODS: Data of a retrospective cohort of 117,598 patients from 750 hospitals, who had undergone tonsillectomy between 2010 and 2016, were drawn from the Diagnosis Procedure Combination database in Japan and studied. RESULTS: Propensity score-matched analysis showed no significant differences in proportions of reoperation or blood transfusion after tonsillectomy between the treatment (TXA from the day of tonsillectomy) and control groups (1.50% vs. 1.47%, p = 0.64). Instrumental variable analysis also showed no significant differences (odds ratio, 0.98; 95% confidence interval, 0.86-1.13; p = 0.82). Higher proportions of reoperation or blood transfusion were significantly associated with male sex, older age, emergency hospitalization, prolonged anesthesia, and medium hospital volume (annual number of tonsillectomies). CONCLUSIONS: Administration of TXA from the day of tonsillectomy is not associated with reduction in reoperation or blood transfusion rates.

Association between perioperative oral care and postoperative pneumonia after cancer resection: conventional versus high-dimensional propensity score matching analysis.

OBJECTIVES: Perioperative oral care was reported to decrease postoperative pneumonia after cancer resections. However, the effect remains controversial because previous studies were limited due to their small sample sizes and lack of strict control for patient backgrounds. The present study evaluated the association between perioperative oral care and postoperative pneumonia using high-dimensional propensity score (hd-PS) matching to adjust for confounding factors. MATERIALS AND METHODS: Using a Japanese health insurance claims database, we identified patients who underwent surgical treatment of cancer from April 2014 to March 2015. To compare outcomes (postoperative pneumonia and procedure-related complications) between patients with and without perioperative oral care, we performed hd-PS matching and conventional PS matching and chi-square test. RESULTS: We identified 621 patients with oral care and 4374 patients without oral care. The occurrences of postoperative pneumonia were not significantly different between patients with and without oral care in the unmatched (2.9% vs. 3.2%), conventional PS-matched (2.9% vs. 2.9%), or hd-PS-matched (2.9% vs. 3.3%) groups. The occurrences of procedure-related complication were not significantly different between patients with and without oral care in the unmatched (23.8% vs. 24.5%), conventional PS-matched (23.8% vs. 26.4%), or hd-PS-matched (24.4% vs. 27.7%) groups. CONCLUSIONS: There was no significant difference in postoperative pneumonia or procedure-related complications between patients with and without perioperative oral care. CLINICAL RELEVANCE: While maintaining optimal oral care in cancer patients is an important goal, the present study revealed no significant difference in postoperative outcomes. Further investigations would be needed to determine the effect of perioperative oral care.

Risk Factors for Free Flap Failure in 2,846 Patients With Head and Neck Cancer: A National Database Study in Japan.

PURPOSE: The risk factors for an unfavorable outcome after microvascular free flap reconstruction in head and neck cancer are not fully understood. We sought to identify factors affecting the occurrence of free flap failure. MATERIALS AND METHODS: This was a retrospective cohort study using data from the national inpatient database in Japan between 2010 and 2012. We identified patients diagnosed with head and neck cancer who underwent tumor resection and consecutive free flap reconstruction. Cox proportional hazards regression was used to assess risk factors for free flap failure. The threshold for significance was P < .05. Missing data were imputed by using multiple imputation. RESULTS: We identified 2,846 eligible patients. The overall proportion of free flap failure was 3.3%. Free flap failure was associated with diabetes mellitus (hazard ratio [HR], 1.80; 95% confidence interval [95% CI], 1.18 to 2.76; P = .007), peripheral vascular disease (HR, 4.49; 95% CI, 1.61 to 12.52; P = .004), renal failure (HR, 3.67; 95% CI, 1.45 to 9.33; P = .006), preoperative radiotherapy (HR, 2.14; 95% CI, 1.11 to 4.13; P = .022), and duration of anesthesia greater than 18 hours (compared with <12 hours; HR, 2.72; 95% CI, 1.19 to 6.22; P = .018). CONCLUSIONS: Diabetes mellitus, peripheral vascular disease, renal failure, preoperative radiotherapy, and a longer duration of anesthesia were significant predictors of the occurrence of free flap failure.

Impact of Body Mass Index on the Outcomes of Open Reduction for Mandibular Fractures.

PURPOSE: Little is known about the impact of body mass index (BMI) on the postoperative outcomes of open reduction for mandibular fractures. The aim of this study was to investigate the relationship between BMI and short-term outcomes of surgery for mandibular fractures. MATERIALS AND METHODS: We searched the Japanese Diagnosis Procedure Combination database to identify patients who underwent open reduction for mandibular fractures from July 2010 to March 2013. BMI was divided into three groups: less than 18.5 kg/m(2) (underweight), 18.5 to 24.9 kg/m(2) (normal weight), and 25 kg/m(2) or greater (overweight). The outcomes included postoperative complication rates, duration of anesthesia, length of stay, and total costs. We analyzed the relationships between BMI and the outcomes by multivariable regression analyses. RESULTS: We analyzed 309 patients who underwent open reduction for mandibular fractures during the study period. The group with a BMI of 25 kg/m(2) or greater had a significantly longer hospital stay (3.8 days; 95% confidence interval, 0.5 to 7.1 days, P = .03) than the group with a normal BMI. BMI was not significantly associated with duration of anesthesia, postoperative complication rates, or total costs. CONCLUSIONS: Regarding open reduction for mandibular fractures, overweight status may be associated with a prolonged length of stay, but may have little impact on operating time, postoperative morbidity, or overall costs.

Effect of Hospital Volume on Outcomes of Surgery for Cleft Lip and Palate.

PURPOSE: Cleft lip and cleft palate are the most common craniofacial anomalies. However, the effect of hospital volume on outcomes of surgery for cleft lip and palate is unknown. MATERIALS AND METHODS: The Japanese Diagnosis Procedure Combination database was searched to identify patients who underwent surgery for cleft lip and palate from July 2010 through March 2013. Hospital volume was divided into tertiles (≤28, 29 to 82, and ≥83 admissions/yr). Outcomes included total cost, length of hospital stay, duration of anesthesia, and length of antibiotic use. The relation between hospital volume and surgical outcomes was analyzed by multivariable regression analyses. RESULTS: The authors identified 7,405 admissions for cleft lip alone, cleft palate alone, or cleft lip and palate during the study period. Compared with the reference low-volume hospital category, a shorter duration of anesthesia was seen in the medium-volume group (-15 minutes; 95% confidence interval, -37 to 7 minutes) and high-volume group (-22 minutes; 95% confidence interval, -65 to 3 minutes). No statistical associations were observed between hospital volume and total cost or length of stay. Although not statistically important, a higher hospital volume was associated with a shorter length of antibiotic use after adjusting for duration of anesthesia. CONCLUSION: In the present study of surgical outcomes for cleft lip and palate, hospital volume was inversely associated with duration of anesthesia and length of antibiotic use, but was not statistically associated with length of hospital stay or total cost.

Preventive dental care reduces risk of cardiovascular disease and pneumonia in hemodialysis population: a nationwide claims database analysis.

This study aims to investigate the impact of dental care utilization status on the occurrence of fatal complications such as cerebral/cardiovascular disease (CVD) and infectious diseases in patients with end-stage renal disease (ESRD) undergoing hemodialysis. This retrospective cohort study was performed using the Japanese claims database and included patients who first underwent hemodialysis between April 2014 and September 2020. The exposure variable of interest was the pattern of dental utilization, which was categorized into three groups, "dental treatment group", "preventive dental care group", and "no-dental visit group". The primary outcomes were the time interval until a composite end point of first major cardiovascular event (acute myocardial infarction, heart failure, or cerebral infarction) of infectious disease (pneumonia and sepsis). The secondary outcomes were the time interval until the incidence of each component of primary outcomes. Survival analyses, including log-rank tests and Cox proportional hazards regression analyses, were performed. Among the 10,873 patients who underwent the first dialysis treatment, 6152 were assigned to the no-dental visit group, 2221 to the dental treatment group, and 2500 to the preventive dental care group. The preventive dental care group had significantly lower hazard ratios (HRs) of the incidence of CVD (adjusted hazard ratio [aHR]: 0.86, 95% confidence interval [CI]: 0.77-0.96) and infectious diseases (aHR: 0.86, 95% CI: 0.76-0.97). As for pneumonia, preventive dental care and dental treatment groups had significantly lower HRs (aHR: 0.74 and 0.80, 95% CI: 0.61-0.88, 0.66-0.96) than the no-dental visit group. This study demonstrated that dental visits for preventive dental care were associated with a significant risk reduction in CVD and infectious complications in patients with ESRD undergoing hemodialysis.