Clinical prediction rules for failed nonoperative reduction of intussusception

Jiraporn Khorana,1 Jayanton Patumanond,2 Nuthapong Ukarapol,3 Mongkol Laohapensang,4 Pannee Visrutaratna,5 Jesda Singhavejsakul1 1Department of Surgery, Division of Pediatric Surgery, Chiang Mai University Hospital, Chiang Mai, 2Center of Excellence in Applied Epidemiology, Thammasat University Hospital, Bangkok, 3Department of Pediatrics, Division of Gastroenterology, Chiang Mai University Hospital, Chiang Mai, 4Department of Surgery, Division of Pediatric Surgery, Siriraj Hospital, Mahidol University, Bangkok, 5Department of Radiology, Chiang Mai University Hospital, Chiang Mai, Thailand Purpose: The nonoperative reduction of intussusception in children can be performed safely if there are no contraindications. Many risk factors associated with failed reduction were defined. The aim of this study was to develop a scoring system for predicting the failure of nonoperative reduction using various determinants.Patients and methods: The data were collected from Chiang Mai University Hospital and Siriraj Hospital from January 2006 to December 2012. Inclusion criteria consisted of patients with intussusception aged 0–15 years with no contraindications for nonoperative reduction. The clinical prediction rules were developed using significant risk factors from the multivariable analysis.Results: A total of 170 patients with intussusception were included in the study. In the final analysis model, 154 patients were used for identifying the significant risk factors of failure of reduction. Ten factors clustering by the age of 3 years were identified and used for developing the clinical prediction rules, and the factors were as follows: body weight <12 kg (relative risk [RR] =1.48, P=0.004), duration of symptoms >48 hours (RR =1.26, P<0.001), vomiting (RR =1.63, P<0.001), rectal bleeding (RR =1.50, P<0.001), abdominal distension (RR =1.60, P=0.003), temperature >37.8°C (RR =1.51, P<0.001), palpable mass (RR =1.26, P<0.001), location of mass (left over right side RR =1.48, P<0.001), ultrasound showed poor prognostic signs (RR =1.35, P<0.001), and the method of reduction (hydrostatic over pneumatic, RR =1.34, P=0.023). Prediction scores ranged from 0 to 16. A high-risk group (scores 12–16) predicted a greater chance of reduction failure (likelihood ratio of positive [LR+] =18.22, P<0.001). A low-risk group (score 0–11) predicted a lower chance of reduction failure (LR+ =0.79, P<0.001). The performance of the scoring model was 80.68% (area under the receiver operating characteristic curve).Conclusion: This scoring guideline was used to predict the results of nonoperative reduction and forecast the prognosis of the failed reduction. The usefulness of these prediction scores is for informing the parents before the reduction. This scoring system can be used as a guide to promote the possible referral of the cases to tertiary centers with facilities for nonoperative reduction if possible. Keywords: intussusception, nonoperative reduction, failure rate, clinical prediction rule

Clinical prediction rules for failed nonoperative reduction of intussusception

Jiraporn Khorana,1 Jayanton Patumanond,2 Nuthapong Ukarapol,3 Mongkol Laohapensang,4 Pannee Visrutaratna,5 Jesda Singhavejsakul1 1Department of Surgery, Division of Pediatric Surgery, Chiang Mai University Hospital, Chiang Mai, 2Center of Excellence in Applied Epidemiology, Thammasat University Hospital, Bangkok, 3Department of Pediatrics, Division of Gastroenterology, Chiang Mai University Hospital, Chiang Mai, 4Department of Surgery, Division of Pediatric Surgery, Siriraj Hospital, Mahidol University, Bangkok, 5Department of Radiology, Chiang Mai University Hospital, Chiang Mai, Thailand Purpose: The nonoperative reduction of intussusception in children can be performed safely if there are no contraindications. Many risk factors associated with failed reduction were defined. The aim of this study was to develop a scoring system for predicting the failure of nonoperative reduction using various determinants.Patients and methods: The data were collected from Chiang Mai University Hospital and Siriraj Hospital from January 2006 to December 2012. Inclusion criteria consisted of patients with intussusception aged 0–15 years with no contraindications for nonoperative reduction. The clinical prediction rules were developed using significant risk factors from the multivariable analysis.Results: A total of 170 patients with intussusception were included in the study. In the final analysis model, 154 patients were used for identifying the significant risk factors of failure of reduction. Ten factors clustering by the age of 3 years were identified and used for developing the clinical prediction rules, and the factors were as follows: body weight <12 kg (relative risk [RR] =1.48, P=0.004), duration of symptoms >48 hours (RR =1.26, P<0.001), vomiting (RR =1.63, P<0.001), rectal bleeding (RR =1.50, P<0.001), abdominal distension (RR =1.60, P=0.003), temperature >37.8°C (RR =1.51, P<0.001), palpable mass (RR =1.26, P<0.001), location of mass (left over right side RR =1.48, P<0.001), ultrasound showed poor prognostic signs (RR =1.35, P<0.001), and the method of reduction (hydrostatic over pneumatic, RR =1.34, P=0.023). Prediction scores ranged from 0 to 16. A high-risk group (scores 12–16) predicted a greater chance of reduction failure (likelihood ratio of positive [LR+] =18.22, P<0.001). A low-risk group (score 0–11) predicted a lower chance of reduction failure (LR+ =0.79, P<0.001). The performance of the scoring model was 80.68% (area under the receiver operating characteristic curve).Conclusion: This scoring guideline was used to predict the results of nonoperative reduction and forecast the prognosis of the failed reduction. The usefulness of these prediction scores is for informing the parents before the reduction. This scoring system can be used as a guide to promote the possible referral of the cases to tertiary centers with facilities for nonoperative reduction if possible. Keywords: intussusception, nonoperative reduction, failure rate, clinical prediction rule

Enema reduction of intussusception: the success rate of hydrostatic and pneumatic reduction

Jiraporn Khorana,1 Jesda Singhavejsakul,1 Nuthapong Ukarapol,2 Mongkol Laohapensang,3 Junsujee Wakhanrittee,4 Jayanton Patumanond5 1Division of Pediatric Surgery, Department of Surgery, 2Division of Gastroenterology, Department of Pediatrics, Chiang Mai University Hospital, Chiang Mai, 3Division of Pediatric Surgery, Department of Surgery, Siriraj Hospital, Mahidol University, Bangkok, 4Division of Pediatric Surgery, Department of Surgery, Thammasat University Hospital, 5Center of Excellence in Applied Epidemiology, Thammasat University Hospital, Pathumthani, Thailand Purpose: Intussusception is a common surgical emergency in infants and children. The incidence of intussusception is from one to four per 2,000 infants and children. If there is no peritonitis, perforation sign on abdominal radiographic studies, and nonresponsive shock, nonoperative reduction by pneumatic or hydrostatic enema can be performed. The purpose of this study was to compare the success rates of both the methods.Methods: Two institutional retrospective cohort studies were performed. All intussusception patients (ICD-10 code K56.1) who had visited Chiang Mai University Hospital and Siriraj Hospital from January 2006 to December 2012 were included in the study. The data were obtained by chart reviews and electronic databases, which included demographic data, symptoms, signs, and investigations. The patients were grouped according to the method of reduction followed into pneumatic reduction and hydrostatic reduction groups with the outcome being the success of the reduction technique.Results: One hundred and seventy episodes of intussusception occurring in the patients of Chiang Mai University Hospital and Siriraj Hospital were included in this study. The success rate of pneumatic reduction was 61% and that of hydrostatic reduction was 44% (P=0.036). Multivariable analysis and adjusting of the factors by propensity scores were performed; the success rate of pneumatic reduction was 1.48 times more than that of hydrostatic reduction (P=0.036, 95% confidence interval [CI] =1.03–2.13).Conclusion: Both pneumatic and hydrostatic reduction can be performed safely according to the experience of the radiologist or pediatric surgeon and hospital setting. This study showed that pneumatic reduction had a higher success rate than hydrostatic reduction. Keywords: intussusception, pneumatic reduction, hydrostatic reduction, success rate&nbsp

Necrotizing fasciitis: epidemiology and clinical predictors for amputation

Patcharin Khamnuan,1,2 Wilaiwan Chongruksut,3 Kijja Jearwattanakanok,4 Jayanton Patumanond,5 Apichat Tantraworasin3 1Clinical Epidemiology Program, Faculty of Medicine, Chiang Mai University, Chiang Mai, 2Department of Nursing, Phayao Hospital, Phayao, 3Department of Surgery, Faculty of Medicine, Chiang Mai University, 4Department of Surgery, Nakornping Hospital, Chiang Mai, 5Clinical Epidemiology Unit, Clinical Research Center, Faculty of Medicine, Thammasat University, Pathum Thani, Thailand Background: Necrotizing fasciitis, a relatively uncommon infection involving the skin, subcutaneous tissue, and fascia, is a rapidly progressive soft tissue infection and a medical and surgical urgency. Delayed debridement, with subsequent huge soft tissue loss is associated with loss of limb and infection and is the most common cause of mortality. The purpose of this work is to describe the epidemiology of necrotizing fasciitis and to identify the clinical characteristics that may be used to predict amputation in routine clinical practice. Methods: Retrospective cohort study data were collected from three general hospitals located in the Chiang Rai, Kamphaeng Phet, and Phayao provinces in northern Thailand. Epidemiologic data for all patients with a surgically confirmed diagnosis of necrotizing fasciitis between 2009 and 2012 were collected. Medical records and reviews were retrieved from inpatient records, laboratory reports, and registers. Clinical predictors for amputation were analyzed by multivariable risk regression. Results: A total of 1,507 patients with a diagnosis of necrotizing fasciitis were classified as being with amputation (n=127, 8.4%) and without amputation (n=1,380, 91.6%). The most common causative Gram-positive and Gram-negative pathogens were Streptococcus pyogenes (33.3% in the amputation group and 40.8% in the non-amputation group) and Escherichia coli (25% in the amputation group and 17.1% in the non-amputation group). Predictive factors for amputation included gangrene (risk ratio [RR] 4.77, 95% confidence interval [CI] 2.70–8.44), diabetes mellitus (RR 3.08, 95% CI 1.98–4.78), skin necrosis (RR 2.83, 95% CI 2.52–3.18), soft tissue swelling (RR 1.76, 95% CI 1.24–2.49), and serum creatinine values ≥1.6 mg/dL on admission (RR 1.71, 95% CI 1.38–2.12). All data were analyzed using the multivariable risk regression generalized linear model. Conclusion: The most causative pathogens were S. pyogenes and E. coli. Clinical predictors for amputation in patients with necrotizing fasciitis included having diabetes mellitus, soft tissue swelling, skin necrosis, gangrene, and serum creatinine values ≥1.6 mg/dL on admission. Thus, patients with any of these predictors should be monitored closely for progression and receive early aggressive treatment to avoid limb loss. Keywords: necrotizing fasciitis, clinical predictors, amputatio

Development of gender- and age group-specific equations for estimating body weight from anthropometric measurement in Thai adults

Kaweesak Chittawatanarat1,2, Sakda Pruenglampoo3, Vibul Trakulhoon4, Winai Ungpinitpong5, Jayanton Patumanond21Department of Surgery, Faculty of Medicine, 2Clinical Epidemiology Unit, 3Research Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand; 4Department of Surgery, Bhumibol Adulyadej Hospital, Bangkok, Thailand; 5Surgical Unit, Surin Hospital, Surin, ThailandBackground: Many medical procedures routinely use body weight as a parameter for calculation. However, these measurements are not always available. In addition, the commonly used visual estimation has had high error rates. Therefore, the aim of this study was to develop a predictive equation for body weight using body circumferences.Methods: A prospective study was performed in healthy volunteers. Body weight, height, and eight circumferential level parameters including neck, arm, chest, waist, umbilical level, hip, thigh, and calf were recorded. Linear regression equations were developed in a modeling sample group divided by sex and age (younger <60 years and older ≥60 years). Original regression equations were modified to simple equations by coefficients and intercepts adjustment. These equations were tested in an independent validation sample.Results: A total of 2000 volunteers were included in this study. These were randomly separated into two groups (1000 in each modeling and validation group). Equations using height and one covariate circumference were developed. After the covariate selection processes, covariate circumference of chest, waist, umbilical level, and hip were selected for single covariate equations (Sco). To reduce the body somatotype difference, the combination covariate circumferences were created by summation between the chest and one torso circumference of waist, umbilical level, or hip and used in the equation development as a combination covariate equation (Cco). Of these equations, Cco had significantly higher 10% threshold error tolerance compared with Sco (mean percentage error tolerance of Cco versus Sco [95% confidence interval; 95% CI]: 76.9 [74.2–79.6] versus 70.3 [68.4–72.3]; P < 0.01, respectively). Although simple covariate equations had more evidence errors than the original covariate equations, there was comparable error tolerance between the types of equations (original versus simple: 74.5 [71.9–77.1] versus 71.7 [69.2–74.3]; P = 0.12, respectively). The chest containing covariate (C) equation had the most appropriate performance for Sco equations (chest versus nonchest: 73.4 [69.7–77.1] versus 69.3 [67.0–71.6]; P = 0.03, respectively). For Cco equations, although there were no differences between covariates using summation of chest and hip (C+Hp) and other Cco but C+Hp had a slightly higher performance validity (C+Hp versus other Cco [95% CI]: 77.8 [73.2–82.3] versus 76.5 [72.7–80.2]; P = 0.65, respectively).Conclusion: Body weight can be predicted by height and circumferential covariate equations. Cco had more Sco error tolerance. Original and simple equations had comparable validity. Chest- and C+Hp-containing covariate equations had more precision within the Sco and Cco equation types, respectively.Keywords: body weight, anthropometry, circumference, Thai, linear model

Clinical predictive score of intracranial hemorrhage in mild traumatic brain injury

Chaiyaporn Yuksen,1 Yuwares Sittichanbuncha,1 Jayanton Patumanond,2 Sombat Muengtaweepongsa,3 Kittisak Sawanyawisuth4,5 1Department of Emergency Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, 2Clinical Epidemiology Unit and Clinical Research Center, Faculty of Medicine, Thammasat University, Pathum Thani, 3Department of Medicine, Faculty of Medicine, Thammasat University, Pathum Thani, 4Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, 5Sleep Apnea Research Group, Research Center in Back, Neck, Other Joint Pain and Human Performance (BNOJPH), and Research and Training Center for Enhancing Quality of Life of Working Age People, Khon Kaen University, Khon Kaen, Thailand Background: Mild traumatic brain injury (TBI) is a common condition at the Emergency Medicine Department. Head computer tomography (CT) scans in mild TBI patients must be properly justified in order to avoid unnecessary exposure to X-rays and to reduce the hospital/transfer costs. This study aimed to evaluate which clinical factors are associated with intracranial hemorrhage in Asian population and to develop a user-friendly predictive model.Methods: The study was conducted retrospectively at the Emergency Medicine Department in Ramathibodi Hospital, a university-affiliated super tertiary care hospital in Bangkok, Thailand. The study period was between September 2013 and August 2016. The inclusion criteria were age >15 years and having received a head CT scan after presenting with mild TBI. Those patients with mild TBI and no symptoms/deterioration after 24 h of clinical observation were excluded. The predictive model and prediction score for intracranial hemorrhage was developed by multivariate logistic regression analysis.Results: During the study period, there were 708 patients who met the study criteria. Of those, 100 patients (14.12%) had positive head CT scan results. There were seven independent factors that were predictive of intracranial hemorrhage. The clinical risk scores to predict intracranial hemorrhage are developed with an accuracy of 92%. The score of >3 had the likelihood of intracranial hemorrhage by 1.47 times.Conclusion: Clinical predictive score of >3 was associated with intracranial hemorrhage in mild TBI. Keywords: predictive model, CT brain, risk scor

Clinical predictors for severe sepsis in patients with necrotizing fasciitis: an observational cohort study in northern Thailand

Patcharin Khamnuan,1,2 Wilaiwan Chongruksut,3 Kijja Jearwattanakanok,4 Jayanton Patumanond,5 Apichat Tantraworasin,3 1Clinical Epidemiology Program, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; 2Department of Nursing, Phayao Hospital, Phayao, Thailand; 3Department of Surgery, Faculty of Medicine, Chiang Mai University, 4Department of Surgery, Nakornping Hospital, Chiang Mai, Thailand; 5Clinical Epidemiology Unit, Clinical Research Center, Faculty of Medicine, Thammasat University, Pathum Thani, Thailand Background: Necrotizing fasciitis (NF) is a life-threatening infection of skin and fascia. Its progress is extremely fast, with extensive necrosis. Delay in treatment, with subsequent huge soft tissue loss and associated severe sepsis, remains a major cause of death in the management of NF. Objective: The aim of this study was to explore clinical characteristics that may be used to predict severe sepsis in patients with NF, in the context of routine clinical practice in northern Thailand. Methods: A retrospective observational cohort study was conducted. The patient cohort in this study consisted of all patients who were diagnosed with NF by surgical or pathological confirmation. The follow-up period started with the admission date and ended with the discharge date. The clinical variables were collected from patients registered at three provincial hospitals in northern Thailand from 2009 to 2012. The clinical predictors for severe sepsis were analyzed using multivariable risk regression. Results: A total of 1,452 patients were diagnosed with NF, either with severe sepsis (n=237 [16.3%]) or without severe sepsis (n=1,215 [83.7%]). From the multivariable analysis, female sex (relative risk [RR] =1.51; 95% confidence interval [CI] =1.04–2.20), diabetes mellitus (RR =1.40; 95% CI =1.25–1.58), chronic heart disease (RR =1.31; 95% CI =1.15–1.49), hemorrhagic bleb (RR =1.47; 95% CI =1.32–1.63), skin necrosis (RR =1.45; 95% CI =1.34–1.57), and serum protein <6 g/dL (RR =2.67; 95% CI =1.60–4.47) were all predictive factors for severe sepsis. Conclusion: The clinical predictors for severe sepsis in patients with suspicion of NF included female sex, diabetes mellitus, chronic heart disease, hemorrhagic bleb, skin necrosis, and serum protein ,6 d/dL. The risk ratio was much higher in patients with total protein <6 g/dL, which is associated with malnutrition. Therefore, provision of sufficient nutritional support and close monitoring for these clinical predictors may be beneficial to reduce morbidity and mortality. Keywords: Necrotizing fasciitis, severe sepsis, clinical predictor

Necrotizing fasciitis: risk factors of mortality

Patcharin Khamnuan,1,2 Wilaiwan Chongruksut,3 Kijja Jearwattanakanok,4 Jayanton Patumanond,5 Suttida Yodluangfun,6 Apichat Tantraworasin31Clinical Epidemiology Program, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; 2Department of Nursing, Phayao Hospital, Phayao, Thailand; 3Department of Surgery, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; 4Department of Surgery, Nakornping Hospital, Chiang Mai, Thailand; 5Clinical Epidemiology Unit, Clinical Research Center, Faculty of Medicine, Thammasat University, Pathum Thani, Thailand; 6Department of Nursing, Chiangrai Prachanukroh Hospital, Chiang Rai, ThailandBackground: Necrotizing fasciitis (NF) is a serious infection of skin and soft tissues that rapidly progresses along the deep fascia. It becomes a fatal soft tissue infection with high mortality rate if treatment is delayed. Early diagnosis for emergency surgical debridement and broad-spectrum antibiotic therapy were the optimal treatments to reduce the mortality rate of NF.Objective: The aim of this study was to identify risk factors that increased the mortality rate in patients with NF under routine clinical practices.Methods: A retrospective cohort study was performed at three general hospitals located in northern Thailand. All medical records of patients with surgically confirmed NF treated between January 2009 and December 2012 were reviewed. Clinical predictors for mortality were analyzed using multivariable risk regression analysis.Results: Of a total of 1,504 patients with a diagnosis of NF, 19.3% (n=290) died in hospital and 80.7% (n=1,214) survived. From multivariable analysis, being female (risk ratio [RR] =1.37, 95% confidence interval [CI] =1.01–1.84); age >60 (RR =1.39, 95% CI =1.25–1.53); having chronic heart disease (RR =1.64, 95% CI =1.18–2.28), cirrhosis (RR =2.36, 95% CI =1.70–3.27), skin necrosis (RR =1.22, 95% CI =1.15–1.28), pulse rate >130/min (RR =2.26, 95% CI =1.79–2.85), systolic BP <90 mmHg (RR =2.05, 95% CI =1.44–2.91), and serum creatinine ≥1.6 mg/dL (RR =3.06, 95% CI =2.08–4.50) were risk factors for mortality.Conclusion: Prognostic factors for mortality in NF patients included being female; age >60; or having chronic heart disease, cirrhosis, skin necrosis, pulse rate >130/min, systolic BP <90 mmHg, and serum creatinine ≥1.6 mg/dL. Thus, disease progression to mortality may occur in such patients presenting one of these risk factors. Further examination or close monitoring for systemic involvement may be advantageous to reduce morbidity and mortality.Keywords: clinical predictors, risk factor, mortality, necrotizing fasciiti

Clinical risk-scoring algorithm to forecast scrub typhus severity

Pamornsri Sriwongpan,1,2 Pornsuda Krittigamas,3 Hutsaya Tantipong,4 Jayanton Patumanond,5 Chamaiporn Tawichasri,6 Sirianong Namwongprom1,71Clinical Epidemiology Program, Chiang Mai University, Chiang Mai, Thailand; 2Department of Social Medicine, Chiangrai Prachanukroh Hospital, Chiang Rai, Thailand; 3Department of General Pediatrics, Nakornping Hospital, Chiang Mai, Thailand; 4Department of Medicine, Chonburi Hospital, Chonburi, Thailand; 5Clinical Epidemiology Program, Thammasat University, Bangkok, Thailand; 6Clinical Epidemiology Society at Chiang Mai, Chiang Mai, Thailand; 7Department of Radiology, Chiang Mai University, Chiang Mai, ThailandPurpose: To develop a simple risk-scoring system to forecast scrub typhus severity.Patients and methods: Seven years' retrospective data of patients diagnosed with scrub typhus from two university-affiliated hospitals in the north of Thailand were analyzed. Patients were categorized into three severity groups: nonsevere, severe, and dead. Predictors for severity were analyzed under multivariable ordinal continuation ratio logistic regression. Significant coefficients were transformed into item score and summed to total scores.Results: Predictors of scrub typhus severity were age >15 years, (odds ratio [OR] =4.09), pulse rate >100/minute (OR 3.19), crepitation (OR 2.97), serum aspartate aminotransferase >160 IU/L (OR 2.89), serum albumin ≤3.0 g/dL (OR 4.69), and serum creatinine >1.4 mg/dL (OR 8.19). The scores which ranged from 0 to 16, classified patients into three risk levels: non-severe (score ≤5, n=278, 52.8%), severe (score 6–9, n=143, 27.2%), and fatal (score ≥10, n=105, 20.0%). Exact severity classification was obtained in 68.3% of cases. Underestimations of 5.9% and overestimations of 25.8% were clinically acceptable.Conclusion: The derived scrub typhus severity score classified patients into their severity levels with high levels of prediction, with clinically acceptable under- and overestimations. This classification may assist clinicians in patient prognostication, investigation, and management. The scoring algorithm should be validated by independent data before adoption into routine clinical practice.Keywords: severe scrub typhus, risk-scoring system, clinical prediction rule, prognostic predictor

Clinical indicators for severe prognosis of scrub typhus

Pamornsri Sriwongpan,1,2 Pornsuda Krittigamas,3 Pacharee Kantipong,4 Naowarat Kunyanone,5 Jayanton Patumanond,1 Sirianong Namwongprom1,61Clinical Epidemiology Program, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; 2Department of Social Medicine, Chiang Rai Prachanukroh Hospital, Chiang Rai, Thailand; 3Department of General Pediatrics, Nakornping Hospital, Chiang Mai, Thailand; 4Department of Internal Medicine, 5Department of Medical Technology, Chiang Rai Prachanukroh Hospital, Chiang Rai, Thailand; 6Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, ThailandBackground: The study explored clinical risk characteristics that may be used to forecast scrub typhus severity under routine clinical practices.Methods: Retrospective data were collected from patients registered at two university-affiliated tertiary care hospitals in the north of Thailand, from 2004 to 2010. Key information was retrieved from in-patient records, out patient cards, laboratory reports and registers. Patients were classified into three severity groups: nonsevere, severe (those with at least one organ involvement), and deceased. Prognostic characteristics for scrub typhus severity were analyzed by a multivariable ordinal continuation ratio regression.Results: A total of 526 patients were classified into nonsevere (n = 357), severe (n = 100), and deceased (n = 69). The significant multivariable prognostic characteristics for scrub typhus severity were increased body temperature (odds ratio [OR] = 0.58, 95% confidence interval [CI] = 0.45&ndash;0.74, P < 0.001), increased pulse rate (OR = 1.03, 95% CI = 1.01&ndash;1.05, P < 0.001), presence of crepitation (OR = 3.25, 95% CI = 1.52&ndash;6.96, P = 0.001), increased percentage of lymphocytes (OR = 0.97, 95% CI = 0.95&ndash;0.98, P = 0.001), increased aspartate aminotransferase (every 10 IU/L) (OR = 1.04, 95% CI = 1.02&ndash;1.06, P < 0.001), increased serum albumin (OR = 0.47, 95% CI = 0.27&ndash;0.80, P = 0.001), increased serum creatinine (OR = 1.83, 95% CI = 1.50&ndash;2.24, P < 0.001), and increased levels of positive urine albumin (OR = 1.43, 95% CI = 1.17&ndash;1.75, P < 0.001).Conclusion: Patients suspicious of scrub typhus with low body temperature, rapid pulse rate, presence of crepitation, low percentage of lymphocyte, low serum albumin, elevated aspartate aminotransferase, elevated serum creatinine, and positive urine albumin should be monitored closely for severity progression.Keywords: severe scrub typhus, risk factors, rickettsial infection, complication