this prospective cross - sectional observational study was conducted in the department of pharmacology and department of medicine over a period of 12 months ( may 2013may 2014 ) . prior to initiation of the study , approval of the research protocol evaluation committee and the institutional ethics committee was obtained . the schedule contained information on demographic variables along with a format for assessing the utilization of anti - diabetic drugs . patients included in this study were conclusively diagnosed to be diabetics and were receiving antidiabetic medication . patients with gestational diabetes and those below 18 years of age were excluded from the study . data were obtained twice a week at the medicine opd , and all diabetic patients admitted in the in - patient facility were screened at least once a week . patients were explained about the purpose of the study and strict confidentiality was ensured . written informed consent was taken from each participant . all the anti - diabetic agents were classified into six major groups and one miscellaneous group . these included the biguanides ( anatomical - therapeutic - chemical classification code - a10ba ) , sulfonylureas ( atc code - a10bb ) , alpha - glucosidase inhibitor ( atc code - a10bf ) , dipeptidyl peptidase 4 inhibitor ( dpp-4 )  ( atc code - a10bh ) , thiazolidinediones ( atc code - a10bg ) , insulin and analogues ( atc code - a10a ) , and other blood glucose lowering drugs ( e.g. , nateglinide , exenatide , repaglinide , etc . ) excluding insulins ( atc code - a10bx ) . the generic names of drugs prescribed by brand names were obtained from the recent editions of current index of medical specialty and indian drug review . the data thus obtained were sorted and categorized on the basis of demographic characteristics ( male vs. female ) , hospital setting ( outpatient vs. inpatient ) , and number of drugs prescribed ( monotherapy vs. combination therapy ) . the national list of essential medicines of india ( nlem ) , 2011 which is published by the ministry of health and family welfare , government of india , was referred . the data collected were analyzed for frequency , percentage , mean , and standard deviation . statistical software used was microsoft office excel 2007 and ibm spss statistics version 20 ( statistical package for the social sciences ibm corporation ) . chi - square test was used where applicable and p < 0.05 was considered significant . this prospective cross - sectional observational study was conducted in the department of pharmacology and department of medicine over a period of 12 months ( may 2013may 2014 ) . prior to initiation of the study , approval of the research protocol evaluation committee and the institutional ethics committee was obtained . the schedule contained information on demographic variables along with a format for assessing the utilization of anti - diabetic drugs . patients included in this study were conclusively diagnosed to be diabetics and were receiving antidiabetic medication . patients with gestational diabetes and those below 18 years of age were excluded from the study . data were obtained twice a week at the medicine opd , and all diabetic patients admitted in the in - patient facility were screened at least once a week . patients were explained about the purpose of the study and strict confidentiality was ensured . written informed consent was taken from each participant . all the anti - diabetic agents were classified into six major groups and one miscellaneous group . these included the biguanides ( anatomical - therapeutic - chemical classification code - a10ba ) , sulfonylureas ( atc code - a10bb ) , alpha - glucosidase inhibitor ( atc code - a10bf ) , dipeptidyl peptidase 4 inhibitor ( dpp-4 )  ( atc code - a10bh ) , thiazolidinediones ( atc code - a10bg ) , insulin and analogues ( atc code - a10a ) , and other blood glucose lowering drugs ( e.g. , nateglinide , exenatide , repaglinide , etc . ) excluding insulins ( atc code - a10bx ) . the generic names of drugs prescribed by brand names were obtained from the recent editions of current index of medical specialty and indian drug review . the data thus obtained were sorted and categorized on the basis of demographic characteristics ( male vs. female ) , hospital setting ( outpatient vs. inpatient ) , and number of drugs prescribed ( monotherapy vs. combination therapy ) . the national list of essential medicines of india ( nlem ) , 2011 which is published by the ministry of health and family welfare , government of india , was referred . the data collected were analyzed for frequency , percentage , mean , and standard deviation . statistical software used was microsoft office excel 2007 and ibm spss statistics version 20 ( statistical package for the social sciences ibm corporation ) . chi - square test was used where applicable and p < 0.05 was considered significant . a total of 310 diabetic patients were included in this study , out of which 307 were suffering from type 2 diabetes mellitus ( t2 dm ) , while three patients had t1 dm . diabetes was found to be more common in females ( 52.3% ) than in males ( 47.7% ) . patients were observed to be mostly in the 6170 years age range ( 27.1% ) followed by 5160 years ( 22.9% ) . as a whole , 71.3% of the patients were above the age of 50 years . disease and demographic characteristics of diabetic patients a total of 560 antidiabetic agents were prescribed during the study period ( 1.84/prescription ) [ table 2 ] . metformin ( biguanide antidiabetic class ) was the single most prescribed antidiabetic agent ( 66.8% of patients ) . glimepiride ( 32.9% ) was the sulfonylureas used most commonly , while glibenclamide was used in 2.6% of the patients . association between the duration of diabetes and insulin usage was found to be significant ( p < 0.05 ) . the utilization of voglibose and sitagliptin was similar ( 21.6% and 21.9% , respectively ) . in terms of total number of antidiabetic units prescribed ( n = 560 ) [ figure 1 ] , the drug share of metformin ( 37% ) was more than that of the sulfonylureas ( 20.7% ) . the utilization of drugs from the nlems was 51.2% , while 11% of antidiabetics were prescribed by their generic name . overall utilization of antidiabetic agents overall utilization of antidiabetics on the basis of total number of units prescribed ( n = 560 ) table 3 depicts the pattern of antidiabetic drug use on the basis of gender . biguanides were prescribed more commonly in males than in females (  = 2.93 ; p = 0.08 ) . sulfonylureas (  = 0.34 ; p = 0.55 ) , insulin (  = 0.002 ; p = 0.95 ) , and thiazolidinediones (  = 2.79 ; p = 0.09 ) were prescribed more commonly in females than in males . however , gender - based differences in the use of the antidiabetic agents were not significant ( p > 0.05 for all groups ) . pattern of antidiabetic drug use on the basis of gender combination antidiabetic drug therapy ( 65.1% ) was used more frequently than monotherapy ( 34.8% ) . a combination of 2 drugs was used in 75.7% of the patients whereas three drug combinations were used in 24.2% of all the patients receiving combination therapy . the most commonly used two drug combinations were metformin + glimepiride ( n = 74 ) and metformin + pioglitazone ( n = 47 ) . the three drug combination of metformin + voglibose + sitagliptin was used in 21 patients , followed by metformin + voglibose + glimepiride , which was used in 13 patients [ figure 2 ] . metformin was a component of 94.7% of all two drug combinations and 100% of all three drug combinations . a total of 48% of all antidiabetic combinations used , comprised both metformin and a sulfonylureas ( n = 96 ) . insulin has been used in combination with metformin and/or a sulfonylureas in eight patients . the use of biguanides (  = 35.68 ; p < 0.0001 ) , sulfonylureas (  = 4.89 ; p = 0.02 ) , and dpp-4 inhibitors (  = 8.1 ; p = 0.004 ) in combination therapy was significant as compared to their use as monotherapy . insulin , on the other hand , was predominantly used as monotherapy in comparison to combination therapy (  = 257.1 ; p < 0.0001 ) [ table 4 ] . relative frequency of anti - diabetic drug combinations used ( n = 202 ) pattern of antidiabetic drug use on the basis of type of therapy table 5 depicts the relative use of antidiabetics in outpatients ( 55.5% ) and inpatients ( 44.5% ) . the use of the thiazolidinedione ( pioglitazone ) was more in outpatients in comparison to that in inpatients , and this difference was highly significant ( p < 0.0001 ;  = 29.25 ) . the biguanides ( p = 0.65 ;  = 0.2 ) and sulfonylureas ( p = 0.08 ;  = 2.9 ) group of antidiabetics were also predominantly used in outpatients as compared to that of inpatients . insulin use was more in inpatients as compared to that of outpatients (  = 44.08 ; p < 0.0001 ) and the difference was highly significant . pattern of antidiabetic drug use on the basis of hospital setting a total of 278 patients had associated comorbidities , the single most common one being hypertension ( 34.5% ) . hypertension alone and comorbid with other conditions / complications such as nephropathy , cerebrovascular accident ( cva ) , and ihd were seen in 74% of the diabetic patients . cva and ihds were seen in 9% and 5.2% of the patients , respectively . other less frequent comorbidities included dyslipidemia , ccf , and copd a total of 310 diabetic patients were included in this study , out of which 307 were suffering from type 2 diabetes mellitus ( t2 dm ) , while three patients had t1 dm . diabetes was found to be more common in females ( 52.3% ) than in males ( 47.7% ) . patients were observed to be mostly in the 6170 years age range ( 27.1% ) followed by 5160 years ( 22.9% ) . as a whole , 71.3% of the patients were above the age of 50 years . a total of 560 antidiabetic agents were prescribed during the study period ( 1.84/prescription ) [ table 2 ] . metformin ( biguanide antidiabetic class ) was the single most prescribed antidiabetic agent ( 66.8% of patients ) . glimepiride ( 32.9% ) was the sulfonylureas used most commonly , while glibenclamide was used in 2.6% of the patients . association between the duration of diabetes and insulin usage was found to be significant ( p < 0.05 ) . the utilization of voglibose and sitagliptin was similar ( 21.6% and 21.9% , respectively ) . in terms of total number of antidiabetic units prescribed ( n = 560 ) [ figure 1 ] , the drug share of metformin ( 37% ) was more than that of the sulfonylureas ( 20.7% ) . human insulin comprised 12.8% of the total drug share . the utilization of drugs from the nlems was 51.2% , while 11% of antidiabetics were prescribed by their generic name . overall utilization of antidiabetic agents overall utilization of antidiabetics on the basis of total number of units prescribed ( n = 560 ) biguanides were prescribed more commonly in males than in females (  = 2.93 ; p = 0.08 ) . sulfonylureas (  = 0.34 ; p = 0.55 ) , insulin (  = 0.002 ; p = 0.95 ) , and thiazolidinediones (  = 2.79 ; . however , gender - based differences in the use of the antidiabetic agents were not significant ( p > 0.05 for all groups ) . pattern of antidiabetic drug use on the basis of gender combination antidiabetic drug therapy ( 65.1% ) was used more frequently than monotherapy ( 34.8% ) . a combination of 2 drugs was used in 75.7% of the patients whereas three drug combinations were used in 24.2% of all the patients receiving combination therapy . the most commonly used two drug combinations were metformin + glimepiride ( n = 74 ) and metformin + pioglitazone ( n = 47 ) . the three drug combination of metformin + voglibose + sitagliptin was used in 21 patients , followed by metformin + voglibose + glimepiride , which was used in 13 patients [ figure 2 ] . metformin was a component of 94.7% of all two drug combinations and 100% of all three drug combinations . a total of 48% of all antidiabetic combinations used , comprised both metformin and a sulfonylureas ( n = 96 ) . insulin has been used in combination with metformin and/or a sulfonylureas in eight patients . the use of biguanides (  = 35.68 ; p < 0.0001 ) , sulfonylureas (  = 4.89 ; p = 0.02 ) , and dpp-4 inhibitors (  = 8.1 ; p = 0.004 ) in combination therapy was significant as compared to their use as monotherapy . insulin , on the other hand , was predominantly used as monotherapy in comparison to combination therapy (  = 257.1 ; p < 0.0001 ) [ table 4 ] . relative frequency of anti - diabetic drug combinations used ( n = 202 ) pattern of antidiabetic drug use on the basis of type of therapy table 5 depicts the relative use of antidiabetics in outpatients ( 55.5% ) and inpatients ( 44.5% ) . the use of the thiazolidinedione ( pioglitazone ) was more in outpatients in comparison to that in inpatients , and this difference was highly significant ( p < 0.0001 ;  = 29.25 ) . the biguanides ( p = 0.65 ;  = 0.2 ) and sulfonylureas ( p = 0.08 ;  = 2.9 ) group of antidiabetics were also predominantly used in outpatients as compared to that of inpatients . insulin use was more in inpatients as compared to that of outpatients (  = 44.08 ; p < 0.0001 ) and the difference was highly significant . a total of 278 patients had associated comorbidities , the single most common one being hypertension ( 34.5% ) . hypertension alone and comorbid with other conditions / complications such as nephropathy , cerebrovascular accident ( cva ) , and ihd were seen in 74% of the diabetic patients . cva and ihds were seen in 9% and 5.2% of the patients , respectively . other less frequent comorbidities included dyslipidemia , ccf , and copd . the who defines drug utilization studies as  the marketing , distribution , prescription , and the use of drugs in a society , with special emphasis on the resulting medical , social , and economic consequences . prescription pattern surveys are an important methodological instrument of drug utilization research , which help to provide an in - depth insight into the disease profile of patients and prescribing behavior of clinicians . such studies can contribute to the promotion of rational , evidence - based drug therapy that can in turn help to improve patient care and treatment . a relative preponderance of diabetes was observed in females , a finding similar to that of studies conducted in nepal and chennai . a study in mysore reported the mean age of diabetics as 56.5  13.2 years , while another study in spain reported it to be 60.5  12.8 years in type 2 diabetics . patients in our study were observed to be mostly in the 6170 years age range ( 27.1% ) followed by 5160 years ( 22.9% ) . in a study done in nepal , most of the patients belonged to the 5160 years age group ( 37.9% ) whereas 21.9% of the patients belonged to the 6170 years age range . all together , the population of diabetics above 50 years of age was 73.63% which was similar to that seen in our study ( 71.3% ) . the findings support the fact that the risk of diabetes tends to increase with age . the mean duration of diabetes was observed to be 9.52  6.5 years which is comparable to the findings of a study done in spain in which the mean duration of diabetes was 11.8  8.0 years . in another study done by john et al . , the mean duration of diabetes was 4.3  4.2 years which was much less than that reported in our study . in the same study , the average number of drugs per prescription was 3.2  1.3 as compared to 4.92  2.5 observed in our study . other factors , such as high number of inpatients and comorbid hypertension , are likely to have had an impact on number of drugs prescribed . it is recognized that patients with dm are generally prescribed more drugs as compared to other patients . metformin monotherapy and combination therapy was used in 66.8% of the patients and was additionally the single most frequently prescribed anti - diabetic drug . this finding is in line with that of upadhyay et al . , where biguanides accounted for 51.2% of the total antidiabetic medications . a study by johnson et al . in canada , similarly observed that 65% of the patients received metformin , alone or in combination . another study in nepal also noted metformin to be the most frequently prescribed antidiabetic agent . however , in some studies conducted in india and abroad , the sulfonylureas group of antidiabetics were observed to be the most commonly prescribed drug class . the fact that metformin was the most frequently prescribed drug in this study is in accordance with its endorsement as the preferred anti - diabetic agent by current clinical guidelines . it has even been recommended as the first choice oral medication in the large subset of elderly diabetics ( > 65 years ) . advantages of metformin that make it the preferred antidiabetic agent include its efficacy in blood sugar reduction without risk of hypoglycemia , greater general tolerability , and relatively lower cost . in obese diabetic patients , it has also been found to significantly reduce glycosylated hemoglobin and all - cause mortality as compared to sulfonylureas and insulin . among the sulfonylureas , glibenclamide was used sparingly ( 2.6% patients ) despite being included in the nlem , whereas glipizide and glimepiride together were prescribed in 34.8% of the patients . this could be due to the fact that glibenclamide is more likely to cause hypoglycemia , particularly in the elderly , consequent to its longer duration of action . on the contrary , other second generation sulfonylureas such as gliclazide , glipizide , and glimepiride are safer than glibenclamide and are preferred . the use of combination antidiabetic therapy ( 65.1% ) was more frequent than that of monotherapy ( 34.8% ) , a finding also observed in a study by rajeshwari et al . , several other studies have also reported the combination of metformin and a sulfonylurea to be used most widely . a combination of metformin and glimepiride , in particular , was the most commonly used drug combination in a study conducted in gujarat where it was prescribed in 76.2% of the patients . clinical studies have shown that a combination of sulfonylureas with metformin can achieve optimal glycemic control even in advanced niddm . broadly speaking , antidiabetics with different mechanisms of action show the greatest synergy , which in turn forms the basis of the guideline recommendation of adding either insulin or sulfonylurea to metformin when the target glycosylated hemoglobin is not achieved . insulin has been used in 23% of the patients , which is similar to the frequency of insulin use in a study by rajeshwari et al . the use of insulin has been observed to be more frequent in inpatients than in outpatients and monotherapy as compared to combination therapy ( p < 0.0001 for both parameters ) . a similar pattern of insulin use was also observed in a study done in mysore . this may suggest that in patients with advanced diabetes and concomitant complications are more likely to require an insulin - based treatment regimen . insulin is mostly indicated when optimal doses of oral hypoglycemic agents do not achieve target glycemic control , and deterioration of glycemic status is associated with substantial weight loss . because of the progressive nature of type 2 diabetes , a substantial proportion of patients are eventually going to require insulin therapy . many studies suggest that t2 dm patients who are intensively being treated with insulin , the combination of insulin and metformin results in superior glycemic control as compared to insulin therapy alone while insulin requirement and weight gain are less . use of metformin in combination with an insulin - based treatment regimen has however been minimal . the use of thiazolidinedione , pioglitazone , and the dpp-4 inhibitor , sitagliptin , has been used mostly in an outpatient hospital setting and in combination with other hypoglycemic agents . the newer oral hypoglycemic agents are likely to be used in combination with the first - line hypoglycemic agents to achieve optimal glycemic control . a significant number of patients with long - term diabetes are at a higher risk of developing complications . the prevalence of hypertension is 1.52 times greater in patients with diabetes mellitus compared with matched non diabetic individuals . conversely , hypertensives are more predisposed to the development of diabetes than their normotensive counterparts . hypertension comorbid with other conditions / complications such as nephropathy , cva , and ihd was seen in 74% of the patients . a high incidence of hypertension comorbid with diabetes was also seen in other studies by rajeshwari et al . and upadhyay et al . since concomitant hypertension increases the risk of development of diabetes - related complications , and vice versa , it is imperative to ensure widespread screening and early detection of both these disorders to impede involvement and progression of end organ damage . rational prescribing practices and the safe use of drugs are very important in the management of diabetic patients since they are likely to be on lifelong therapy . the nlems is aimed at promoting rational use of medicines by considering their cost , safety , and efficacy , thus prioritizing the availability of affordable quality medicine at all levels of healthcare . in our study , the use of antidiabetic agents from the nlem was 51.2% . a slightly higher use of drugs from the nlem was observed in a study by agarwal et al . , prescribing drugs by generic name allows flexibility of stocking and dispensing various brands of a particular drug that are cheaper than and as effective as proprietary brands , and should thus be encouraged . there is a clear emphasis on the overall use of metformin and sulfonylureas as combination therapy , and insulin as monotherapy , particularly in an inpatient hospital setting . evidence - based medicine should be an essential component of continuing medical education to enable advances in clinical research to be translated into best possible patient care practices .