stevens - johnson syndrome ( sjs ) and toxic epidermal necrolysis ( ten ) are life - threatening dermatologic conditions , which predominantly involve the skin and mucous membranes . sjs is characterized by high fever , malaise , and a rapidly developing blistering exanthema of macules and target - like lesion , accompanied by mucosal involvement , whereas ten has similar presentations with even more extensive skin detachment and a higher mortality rate . although the incidence of sjs / ten is as low as 0.4 - 6 persons per million populations each year , their mortality rate has been estimated to be 1 - 50% . moreover , about 30 - 70% of the surviving patients were suffering from long - term sequelae such as severe dry eye syndrome . there are many causes of sjs / ten such as chemical exposures , mycoplasma pneumonia , viral infections , and immunizations but the most common causes are medications . the management of sjs / ten requires substantial health care resources including prolonged hospitalization , aggressive fluid replacement , nutrition support , and antibacterial treatments . a recent study was conducted in india to investigate health care utilization and cost among 32 sjs / ten cases . the length of hospital stay ( los ) for sjs and ten was reported to be 9.7 days [ 95% confidence interval ( ci ) : 5.8 - 13.6 ] and 20.6 days ( 95% ci : 14.4 - 26.8 ) , respectively . the average direct medical cost of care for sjs and ten was approximately $ 38.4 and $ 123.6 per person , respectively . in thailand , the incidence of drug - induced sjs / ten and mortality rate of these conditions is high . the incidence of sjs / ten are 10.35 per 1,000 persons while the mortality rate in the thai population is 7 - 50% . since the incidence and mortality rate of sjs / ten is high relative to other countries , it is important for clinicians and policymakers to understand the economic implications of these conditions . such information on cost and health care resource utilization hence the present study was carried out . a descriptive retrospective study was undertaken to estimate health care resource utilization and cost of care for sjs / ten using an electronic database from a 1,000-bed regional hospital in northern thailand from a hospital perspective . the inpatient database contained information on age , gender , date of birth , health care insurance , and diagnosis code [ international classification of diseases ( icd ) , 10 revision ] , type of diagnosis ( primary or secondary diagnosis ) , adjusted relative weight for each admission , date of admission , date of discharge , and discharge status . the pharmacy database was enriched with information on the generic names of drugs , regimen , and the days when these were supplied . the charge database included information on drugs , laboratory , medical service , and other service charges . the protocol was approved by naresuan university institutional review board ( nuirb ) and the university - affiliated hospital and confidentiality of patients was maintained using unique identifiers . all patients who were admitted to the study hospital from 2002 to 2007 with a diagnosis of sjs or ten were included . the sjs and ten were defined by icd-10 as l51.1 for sjs and l51.2 for ten . the patients who met the inclusion criteria were tracked during the hospitalization episode of sjs / ten which was from the date of admission to the date of discharge . the data of all included patients were collected as follows : demographic data , comorbidities , length of stay , discharge status , treatment patterns for sjs / ten , and cost of sjs / ten care . the primary outcome measure was direct medical cost of care for sjs , ten , and sjs / ten . it was determined using the cost - to - charge ratio ( ccr ) technique as a primary analysis . [(charge  ccr )  cpix / cpi2013 ]   equation 1 where ccr stands for ratio of cost - to - charge in each year cpix stands for consumer price index for the year of data used cpi2013 stands for consumer price index for the year 2013 in a sensitivity analysis , diagnosis - related group ( drg ) technique was used as an alternative method to estimate the direct medical cost using equation 2 . [(br  adjrw )  cpix / cpi2013 ]   equation 2 where br stands for base rate for a hospitalization which is  10,000 ( at year 2007 ) adjrw stands for adjusted relative weight cpix stands for consumer price index for the year of data used cpi2013 stands for consumer price index for the year 2013 briefly , the ccr technique is used to estimate cost of disease management when the actual cost is not available . estimated cost is calculated by multiplying charge , which is usually recorded for reimbursement purpose with crr . the crr is usually calculated by the hospital for administrative purpose . in our study , ccr was calculated by the hospital and was recorded each year while charges of each health care section ( such as drug , laboratory , medical service , and other service charges ) were recorded in the charge database . charge in our study means a payment that the hospital will charge payers with if the payment mechanism is fee - for - service . we calculated cost of care for sjs / ten by multiplying charges recorded in the charge database with ccr of each year , which was provided by hospital staff . the ccr was 0.77 for 2008 and 0.90 for 2007 , 2009 , and 2010 . a total cost of the admission was  15,400 . for drg technique , we calculated cost of care for sjs / ten by multiplying adjusted relative weight ( adjrw ) of each drg with base rate of an admission , which was an amount of money that payers pay for one adjrw . in our study , we used  10,000 for one adjrw . adjrw for each admission was calculated by hospital administrators and recorded in the inpatient database using drg technique . all costs were converted to the value in the year 2013 using an average consumer price index in the medical and personal care sector and converted to $ us using an average exchange rate of  31/$us . secondary outcome measures are length of stay ( los ) , discharge status , and patterns of medication use for treatment . quantitative variables such as age , direct medical cost , and frequency of resource utilization were tested for normal distribution by visualized histograms . the means and standard deviations were used when data were normally distributed while medians and interquartile ranges ( iqrs ) were used when the data were not normally distributed . categorical variables such as gender , comorbidity , and discharge status were described by their frequencies and percentages . subgroup analyses were also performed by separation of sjs and ten patients , and the types of diagnoses were classified as primary diagnosis and secondary diagnosis of sjs / ten . primary diagnosis was identified as a diagnosis contributing the most to the whole hospital stay of the patient while secondary diagnoses were other important diagnoses in the hospital stay such as comorbidities or complications . stata package version 11.0 ( statacorp , college station , tx , usa ) was used for all analyses . a descriptive retrospective study was undertaken to estimate health care resource utilization and cost of care for sjs / ten using an electronic database from a 1,000-bed regional hospital in northern thailand from a hospital perspective . the inpatient database contained information on age , gender , date of birth , health care insurance , and diagnosis code [ international classification of diseases ( icd ) , 10 revision ] , type of diagnosis ( primary or secondary diagnosis ) , adjusted relative weight for each admission , date of admission , date of discharge , and discharge status . the pharmacy database was enriched with information on the generic names of drugs , regimen , and the days when these were supplied . the charge database included information on drugs , laboratory , medical service , and other service charges . the protocol was approved by naresuan university institutional review board ( nuirb ) and the university - affiliated hospital and confidentiality of patients was maintained using unique identifiers . all patients who were admitted to the study hospital from 2002 to 2007 with a diagnosis of sjs or ten were included . the sjs and ten were defined by icd-10 as l51.1 for sjs and l51.2 for ten . the patients who met the inclusion criteria were tracked during the hospitalization episode of sjs / ten which was from the date of admission to the date of discharge . the data of all included patients were collected as follows : demographic data , comorbidities , length of stay , discharge status , treatment patterns for sjs / ten , and cost of sjs / ten care . the primary outcome measure was direct medical cost of care for sjs , ten , and sjs / ten . it was determined using the cost - to - charge ratio ( ccr ) technique as a primary analysis . [(charge  ccr )  cpix / cpi2013 ]   equation 1 where ccr stands for ratio of cost - to - charge in each year cpix stands for consumer price index for the year of data used cpi2013 stands for consumer price index for the year 2013 in a sensitivity analysis , diagnosis - related group ( drg ) technique was used as an alternative method to estimate the direct medical cost using equation 2 . [(br  adjrw )  cpix / cpi2013 ]   equation 2 where br stands for base rate for a hospitalization which is  10,000 ( at year 2007 ) adjrw stands for adjusted relative weight cpix stands for consumer price index for the year of data used cpi2013 stands for consumer price index for the year 2013 briefly , the ccr technique is used to estimate cost of disease management when the actual cost is not available . estimated cost is calculated by multiplying charge , which is usually recorded for reimbursement purpose with crr . the crr is usually calculated by the hospital for administrative purpose . in our study , ccr was calculated by the hospital and was recorded each year while charges of each health care section ( such as drug , laboratory , medical service , and other service charges ) were recorded in the charge database . charge in our study means a payment that the hospital will charge payers with if the payment mechanism is fee - for - service . we calculated cost of care for sjs / ten by multiplying charges recorded in the charge database with ccr of each year , which was provided by hospital staff . the ccr was 0.77 for 2008 and 0.90 for 2007 , 2009 , and 2010 . a total cost of the admission was  15,400 . for drg technique , we calculated cost of care for sjs / ten by multiplying adjusted relative weight ( adjrw ) of each drg with base rate of an admission , which was an amount of money that payers pay for one adjrw . in our study , we used  10,000 for one adjrw . adjrw for each admission was calculated by hospital administrators and recorded in the inpatient database using drg technique . all costs were converted to the value in the year 2013 using an average consumer price index in the medical and personal care sector and converted to $ us using an average exchange rate of  31/$us . secondary outcome measures are length of stay ( los ) , discharge status , and patterns of medication use for treatment . quantitative variables such as age , direct medical cost , and frequency of resource utilization were tested for normal distribution by visualized histograms . the means and standard deviations were used when data were normally distributed while medians and interquartile ranges ( iqrs ) were used when the data were not normally distributed . categorical variables such as gender , comorbidity , and discharge status were described by their frequencies and percentages . subgroup analyses were also performed by separation of sjs and ten patients , and the types of diagnoses were classified as primary diagnosis and secondary diagnosis of sjs / ten . primary diagnosis was identified as a diagnosis contributing the most to the whole hospital stay of the patient while secondary diagnoses were other important diagnoses in the hospital stay such as comorbidities or complications . stata package version 11.0 ( statacorp , college station , tx , usa ) was used for all analyses . one hundred and forty - six patients ( 93.0% ) were diagnosed as sjs and the remaining patients were diagnosed as ten . of those patients , 110 patients were primarily diagnosed as sjs and 8 patients were diagnosed as ten while 36 patients were secondarily diagnosed as sjs , and 3 patients were secondarily diagnosed as ten . infectious , endocrine , and cardiovascular diseases are the most common co - morbidities seen in the patients [ table 1 ] . csmbs = civil servant medical benefit schemes , sd = standard deviation , sss = social security schemes , uc = universal coverage , sjs = stevens  johnson syndrome , ten = toxic epidermal necrolysis , iqr = interquartile range the medications used during the treatment of sjs / ten can be categorized into two groups : supportive and specific treatments . for supportive treatment , acid - suppressing drugs [ h2-blockers , proton pump inhibitor ( ppi ) ] , antianxiety drugs , antihistamine drugs , anesthetic drugs , and analgesic drugs were used . the most common drugs for supportive treatment were antihistamine ( 91.1% ) and analgesic drugs ( 73.2% ) . almost half of the patients also received ophthalmic steroids ( 43.3% ) [ table 2 ] . prednisolone was commonly used as an oral medication while dexamethasone was usually used as an injection medication . medication utilization for sjs / ten sjs = stevens  johnson syndrome , ten = toxic epidermal necrolysis most of the patients recovered after the treatment ( 72.42% ) while 17.8% , 1.9% , and 8.3% of the patients were referred to other treatments , referred against the treatment , and died , respectively . the average los was 10.2  13.6 days in patients with sjs , while it was 8.5  6.2 days in patient with ten . the case - fatality ratio of patients with ten ( 18.2% ) was higher than that of patients with sjs ( 7.5% ) [ table 3 ] . the average los in patients with primary diagnosis as sjs / ten was 6.8  4.8 days while that in patients with secondary diagnosis as sjs / ten was 20.2  22.5 days . the case - fatality ratio of patients with primary and secondary diagnoses was 3.4% and 23.1% , respectively [ table 3 ] . length of stay and discharge status based on types of diagnoses iqr = interquartile range , sd = standard deviation , sjs = stevens - johnson syndrome , ten = toxic epidermal necrolysis overall , based on ccr technique the average cost of care for sjs / ten was $ 1,064  $ 2,558 with the median cost of $ 369 [ iqr ; $ 194 - 870 ] . the average cost estimated by ccr was higher than the cost estimated by drg ( $ 1,064  $ 2,558 vs $ 617  $ 1,224 ) [ table 4 ] . direct medical cost of care for sjs / ten management by diagnosis ( us$ ) iqr = interquartile range , sd = standard deviation , sjs = stevens - johnson syndrome , ten = toxic epidermal necrolysis the average cost of care for patients with sjs was $ 1,019  $ 2,601 while that for patients with ten was $ 1,660  $ 1,887 [ table 4 ] . the average cost of care for cases with sjs / ten as secondary diagnosis ( $ 2,600  $ 4,658 ) was higher than that for primary diagnosis ( $ 556  $ 797 ) [ table 5 ] . a major driver of cost of sjs / ten care was medication cost , which accounted for 41% of the direct medical cost . the service cost , diagnosis cost , and other costs were 22% , 20% , and 17% , respectively . direct medical cost of care for sjs / ten management by types of cost estimation ( us$ ) iqr = interquartile range , sd = standard deviation one hundred and forty - six patients ( 93.0% ) were diagnosed as sjs and the remaining patients were diagnosed as ten . of those patients , 110 patients were primarily diagnosed as sjs and 8 patients were diagnosed as ten while 36 patients were secondarily diagnosed as sjs , and 3 patients were secondarily diagnosed as ten . infectious , endocrine , and cardiovascular diseases are the most common co - morbidities seen in the patients [ table 1 ] . csmbs = civil servant medical benefit schemes , sd = standard deviation , sss = social security schemes , uc = universal coverage , sjs = stevens  johnson syndrome , ten = toxic epidermal necrolysis , iqr = interquartile range the medications used during the treatment of sjs / ten can be categorized into two groups : supportive and specific treatments . for supportive treatment , acid - suppressing drugs [ h2-blockers , proton pump inhibitor ( ppi ) ] , antianxiety drugs , antihistamine drugs , anesthetic drugs , and analgesic drugs were used . the most common drugs for supportive treatment were antihistamine ( 91.1% ) and analgesic drugs ( 73.2% ) . almost half of the patients also received ophthalmic steroids ( 43.3% ) [ table 2 ] . prednisolone was commonly used as an oral medication while dexamethasone was usually used as an injection medication . moreover , dexamethasone was the most commonly used among ophthalmic steroids . medication utilization for sjs most of the patients recovered after the treatment ( 72.42% ) while 17.8% , 1.9% , and 8.3% of the patients were referred to other treatments , referred against the treatment , and died , respectively . the average los was 10.2  13.6 days in patients with sjs , while it was 8.5  6.2 days in patient with ten . the case - fatality ratio of patients with ten ( 18.2% ) was higher than that of patients with sjs ( 7.5% ) [ table 3 ] . the average los in patients with primary diagnosis as sjs / ten was 6.8  4.8 days while that in patients with secondary diagnosis as sjs / ten was 20.2  22.5 days . the case - fatality ratio of patients with primary and secondary diagnoses was 3.4% and 23.1% , respectively [ table 3 ] . length of stay and discharge status based on types of diagnoses iqr = interquartile range , sd = standard deviation , sjs = stevens - johnson syndrome , ten = toxic epidermal necrolysis overall , based on ccr technique the average cost of care for sjs / ten was $ 1,064  $ 2,558 with the median cost of $ 369 [ iqr ; $ 194 - 870 ] . the average cost estimated by ccr was higher than the cost estimated by drg ( $ 1,064  $ 2,558 vs $ 617  $ 1,224 ) [ table 4 ] . direct medical cost of care for sjs / ten management by diagnosis ( us$ ) iqr = interquartile range , sd = standard deviation , sjs = stevens - johnson syndrome , ten = toxic epidermal necrolysis the average cost of care for patients with sjs was $ 1,019  $ 2,601 while that for patients with ten was $ 1,660  $ 1,887 [ table 4 ] . the average cost of care for cases with sjs / ten as secondary diagnosis ( $ 2,600  $ 4,658 ) was higher than that for primary diagnosis ( $ 556  $ 797 ) [ table 5 ] . a major driver of cost of sjs / ten care was medication cost , which accounted for 41% of the direct medical cost . the service cost , diagnosis cost , and other costs were 22% , 20% , and 17% , respectively . direct medical cost of care for sjs / ten management by types of cost estimation ( us$ ) iqr = interquartile range , sd = standard deviation to the best of our knowledge , this study is one of the largest studies describing health care utilization and cost for sjs / ten management . previous studies have been conducted in less than 50 patients while this study was undertaken in more than 150 patients . the results in this study showed crucial information to health policymakers so as to allocate health care resources to manage sjs / ten at the population level efficiently . moreover , the findings raised awareness of clinicians on the importance of sjs / ten and its associated substantial economic loss . the average los found in this study was about 10 days with case - fatality ratio of 8% . these findings were lower than those reported in a previous thai study , which revealed that the average los was 19.2 days with case - fatality ratio of 14% . thus , patients with ten are likely to have a longer length of stay than patients with sjs . this finding might be affected by a smaller group of patients , as only 7% were diagnosed with ten in this study while it was 15.7% in the previous study . there was another thai study reporting the average los of patients with sjs to be 5.3 days . even though the study used a national database from the national health security office , only 15 patients with sjs were determined in addition , our finding indicated longer los in patients with sjs than patients with ten . this could be explained by the fact that patients with ten have higher case - fatality ratio and may have died in short period of time , leading to shorter average los compared to that of patients with sjs . to further address this issue , we performed a post hoc subgroup analysis to explore the los of patients who were cured from sjs or ten . we found that los of sjs survivors was 9.16  9.92 days while the los of ten survivors was 9.33  8.09 days . this supported our discussion point that the reason for shorter los of ten patients compared to sjs patients might be due to higher case - fatality ratio . the majority of patients , which was more than 80% of hospitalized patients , received systematic corticosteroids , along with supportive care . this was similar to a previous thai study , which indicated that the majority of patients ( 76.5% ) admitted to a university hospital received intravenous corticosteroids . it is important to note that there remains a lack of evidence demonstrating the clear benefits of using corticosteroids for sjs / ten management . a number of observational studies found no beneficial effect of systemic corticosteroid compared to supportive care management . to date , several specific medications ( such as intravenous immunoglobulin , thalidomide , cyclosporine , and cyclophosphamide ) have been used to treat sjs / ten without strong supporting evidence . in this study the spending was 19.4% of gross domestic product per capita , which could be considered relatively high . costs in patients with ten and patients with secondary diagnosis were higher than those patients with sjs and patients with secondary diagnosis . the accuracy of cost estimate is important , especially when it is applied to health economic evaluation . sources of data and the number of patients included in the study reflected the accuracy of health care cost estimation . there were three previous cost - effectiveness studies related to sjs / ten in thailand that used different sources of cost for sjs / ten management . estimated the cost of carbamazepine ( cbz)-induced sjs / ten in 15 adult patients using a multicenter retrospective database analysis . the authors found that the average direct medical cost of cbz - induced sjs / ten was  25,868 ( $ 834 ) . the second study was conducted by tiamkao et al . , which included 51 sjs / ten patients . the cost of sjs / ten management in the study was obtained from reimbursement records of a university hospital . they found that the average cost of sjs / ten management was  53,858 ( $ 1,737 ) . the last study was conducted by saokaew et al . , which included 151 patients . the cost of sjs / ten was estimated using a retrospective database analysis from a tertiary care hospital ( 1,000-bed capacity ) . they found that the average direct medical cost was  15,440 ( $ 498 ) . the last study used the cost , which was calculated based on the same source of this study . the previous direct medical cost was lower than the one found in this study , which indicated that the average direct medical cost was $ 1,064 . it is important to note that the result from the previous study was based on only 15 patients with sjs ; its accuracy and precision were questionable . in our study , we descriptively compared the different approaches , which were the ccr and drg approaches to determine cost . this is because the ccr reflects better the average cost incurred in a hospital than drg . however , drg should be applied when cost estimation is based on the payer 's perspective because drg was developed for reimbursement purpose . thus , to select an appropriate method for cost analysis studies , the study perspective should be carefully considered . our subgroup analysis revealed longer los ( 6.8  4.8 days vs 20.2  22.5 ) in patients with secondary diagnosis . furthermore , our finding indicated higher cost in patients with secondary diagnosis as sjs / ten than that in patients with primary diagnosis as sjs / ten ( $ 556  $ 797 vs $ 2,600  $ 4,658 ) . as per the definition used in our study , primary diagnosis was the major diagnosis of the admission or visit while secondary diagnosis was comorbidity or complications . this implies that patients with sjs / ten as secondary diagnosis would have other diseases , which might contribute to the los . the conditions of patients with secondary diagnosis as sjs / ten were likely to be more complicated than of patients with primary diagnosis as sjs / ten . this leads to longer los and higher cost in patients with secondary diagnosis as sjs / ten than in patients with primary diagnosis as sjs / ten . first , our study was conducted in a regional hospital ; generalizability should be limited to hospitals with characteristics similar to this tertiary study setting . diagnostic testing strategies or treatment patterns for sjs / ten management of this hospital might be different from those of other settings , which may increase the cost of sjs / ten management . it is important to note that most patients with sjs / ten are less likely to be hospitalized in a secondary or primary care setting . second , misclassification might have occurred since these findings were based on only electronic databases . third , the estimated costs in this study were based on costs incurred during the hospitalization of patients with sjs / ten . in addition , the study was undertaken from a hospital perspective ; direct nonmedical cost and indirect cost , especially the loss of productivity were not included . further studies determining the total cost of sjs / ten from the societal perspective are still required . lastly , the estimated costs and health care utilization were the overall estimates . there might be some differences in a different level of care such as the intensive care unit and general wards . however , we could not estimate the costs and health care utilization by the level of care because of the limitation on data availability . in conclusion , this study demonstrates the significance of the sjs / ten using thailand as a case study . there remains a need for estimating the costs of sjs / ten management in other developing countries , especially in countries where the prevalence of sjs / ten is high . our findings should be used as a key input parameter for any future cost - effectiveness studies related to sjs / ten in thailand . moreover , policymakers should be concerned and use these findings as an important information for efficient resource allocation . in addition , these findings should be promoted among clinicians to enhance awareness of cost - related sjs / ten and to operate effective actions to prevent sjs / ten from adverse drug events .
background : stevens - johnson syndrome ( sjs ) and toxic epidermal necrolysis ( ten ) are life - threatening dermatologic conditions . although , the incidence of sjs / ten in thailand is high , information on cost of care for sjs / ten is limited . 
 this study aims to estimate healthcare resource utilization and cost of sjs / ten in thailand , using hospital perspective.methods:a retrospective study using an electronic health database from a university - affiliated hospital in thailand was undertaken . 
 patients admitted with sjs / ten from 2002 to 2007 were included . 
 direct medical cost was estimated by the cost - to - charge ratio . 
 cost was converted to 2013 value by consumer price index , and converted to $ us using 31 baht/1 $ us . 
 the healthcare resource utilization was also estimated.results:a total of 157 patients were included with average age of 45.323.0 years . 
 about 146 patients ( 93.0% ) were diagnosed as sjs and the remaining ( 7.0% ) were diagnosed as ten . 
 most of the patients ( 83.4% ) were treated with systemic corticosteroids . 
 overall , mortality rate was 8.3% , while the average length of stay ( los ) was 10.113.2 days . 
 the average cost of managing sjs / ten for all patients was $ 1,064$2,558 . 
 the average cost for sjs patients was $ 1,019$2,601 while that for ten patients was $ 1,660$1,887.conclusions : healthcare resource utilization and cost of care for sjs / ten in thailand were tremendous . 
 the findings are important for policy makers to allocate healthcare resources and develop strategies to prevent sjs / ten which could decrease length of stay and cost of care .