it is estimated that more than 4 million adults had diabetes in 2011 , which showed 35% increment during past 7 years . expanding epidemic of obesity is responsible in large part for a high prevalence of diabetes mellitus and impaired fasting glucose among iranian adults . therefore , an increase in the risk of cardiovascular diseases including coronary heart disease ( chd ) , is anticipated . in fact , the presence of diabetes is somehow considered equivalent to that of a history for chd . consequently , the coexistence of diabetes and hypercholesterolemia further raises the risk of cardiovascular morbidity and mortality . effective lipid lowering therapies especially statins are widely available to decline the cardiovascular risk across a wide range of patients particularly those with type 2 diabetes . patients with type 2 diabetes are benefitted from statin therapy by decreasing the risk of chd and related clinical outcomes . unfortunately , despite the availability of effective pharmacologic treatment and well - publicized therapeutic guidelines , elevated serum cholesterol levels remain uncontrolled in patients with hypercholesterolemia especially those with diabetes . the percentage of controlled cholesterol among united states adults receiving treatment increased from 45.0% in 1999 - 2000 to 63.6% in 2009 - 2010 . however high low - density lipoprotein ( ldl ) cholesterol remains the common problem in health care system . significant gap between expected and actual benefit of statins may be attributed to the lack of enough follow - up or inappropriate titration of the starting statin dose . in addition , poor adherence may be considered amongst the most important reasons of failure to achieve the goals for dyslipidemia . in a retrospective cohort study , the proportion of days covered by statin treatment was 79% among elderly patients ( 23.5% with diabetes ) during the first 3 months . although adherence fell dramatically to 42% after 120 months follow - up . to the best of our knowledge , there is not enough information regarding statin adherence and/or goal attainment rates of ldl cholesterol of patients with type 2 diabetes in developing countries . to address these issues , we conducted a study to evaluate the adequacy of diabetic patients adherence to statin therapy for lipid management in a research based community clinic in iran . we conducted a prospective clinical study in patients with type 2 diabetes under treatment with statins . iemrc is one of the largest outpatient diabetes research centers in the central part of iran which also provides medical care and educational program for patients with diabetes . the study protocol of this observational research project was approved by the institutional board for human studies at isfahan university of medical sciences ( registration number , 3,87,311 ) . all patients received a 15 min explanation of the study protocol in simple language by the principal investigator farsaei and if they announced to join the study , they were recruited . they also were free to leave the study whenever they want without depriving from normal medical care . all patients who took statins were identified during 3 months and included to the study . among enrolled patients who did not have documented ldl cholesterol within 90 days after study inclusion or those who did not keep their scheduled visit 3 months after their initial visit were excluded . totally , 204 patients with diabetes and prescription of statins were included during a 3-month sampling period . pharmacist interviewed patients and filled out demographic data ( age , body mass index [ bmi ] , sex , education ) and statin information ( type , dose and initial number of prescribed statin ) in data gathering form . in addition , data regarding ldl cholesterol over the same period were included to evaluate the relationship between ldl level and statin adherence . since metformin could have a significant effect on lipid profile , data regarding administration dose of metformin were also gathered to compare between groups . all included patients were asked to return 3 months after initial visit for counting remained statins and calculate statin adherence . subsequently , in the second visit remained medications in blisters were counted in all participants and adherence was calculated . in our study with pill count method , adherence of patients was expressed as a percentage of medicines taken during 3 months relative to the number of medicines that should have been taken during the same period . in addition , self - reporting was used to report medication behavior of patients during 3 months . in the same manner patients declared taking < 80% of their prescribed statins were considered nonadherent to their treatment . medication possession ratio ( mpr ) was also calculated during 3 months of study to evaluate its correlation with mean ldl cholesterol level . continuous variables were expressed as mean  standard deviation and categorical data as a percentage . kolmogrov - smirnov test was carried out to assess the distribution of continuous variables . student 's t - test , chi - square , and mann  whitney u - test were used to evaluate results . in addition , pearson correlation was used to evaluate the association between mpr and ldl cholesterol level . , chicago , il , usa ) , and two - tailed p < 0.05 was considered for statistical significance in all analyses . the research protocol for this study was approved by the board of human studies of the isfahan university of medial sciences . continuous variables were expressed as mean  standard deviation and categorical data as a percentage . kolmogrov - smirnov test was carried out to assess the distribution of continuous variables . student 's t - test , chi - square , and mann  whitney u - test were used to evaluate results . in addition , pearson correlation was used to evaluate the association between mpr and ldl cholesterol level . data processing was performed by spss statistical software version 11.5 software ( spss inc . , chicago , il , usa ) , and two - tailed p < 0.05 was considered for statistical significance in all analyses . the research protocol for this study was approved by the board of human studies of the isfahan university of medial sciences . among 204 patients met inclusion criteria , 46 patients were excluded during the study and final analyses were conducted with the data from 158 patients who completed the study [ figure 1 ] . lovastatin was prescribed for more than 98% of patients in our study with dose of 10.2  3.7 mg daily and < 2% of patients received atorvastatin or simvastatin as cholesterol lowering agent . follow - up chart of the studied patients overall , 20.3% ( n = 32 ) of patients were considered nonadherent to statin therapy and only 31.6% ( n = 50 ) of patients achieved their ldl cholesterol goal < 100 mg / dl . although higher percent of males had adherence 80% to statin therapy than females but there was no significant difference between genders [ table 1 ] . once again , the rate of ldl goal attainment was higher among men however it was not significant [ table 2 ] . furthermore , other demographic characteristics including age , bmi , control of diabetes ( hemoglobin a1c ) and education did not significantly affect on adherence and ldl goal achievement [ tables 1 and 2 ] . demographic characteristics of the studied patients and adherence to statin therapy ldl cholesterol goal attainment and related factors in this study , patients with adherence 80% had lower total and ldl cholesterol than those with adherence < 80% ( p < 0.01 ) . moreover , adherent patients reached therapeutic goal significantly more than those who were considered non - adherence to statin therapy ( p < 0.01 ) . in addition , number of prescribed medications had a significant effect on statin adherence and ldl goal attainment . < 100 mg / dl had lower prescribed medication in comparison with adherence < 80% or ldl 100 mg / dl , respectively . according to self - reporting , most of studied population ( 69% ) were adherent to statin and 49 patients ( 31% ) were nonadherent . the mean of mpr of statins during 3 months was 0.89  0.24 and pearson correlation showed the weak inverse relationship between mpr and ldl cholesterol , however this was not statistically significant ( r = 0.16 , p = 0.08 ) . a chi - square test showed that there was a significant relationship between adherence reporting by pill counting and self - reporting ( p < 0.01 ) . since 92% of self - reported adherent patients were also considered , adherent based on pill counting and 50% of patients who reported non - adherence to statin treatment had adherence < 80% according to pill counting . the most frequent barrier to adherence was reported as forgetting to take statins ( 50% ) . discontinuation of medication when ldl cholesterol had been controlled or when patients were outside their home were other frequent factors related to non - adherence . in addition , an insufficient amount of prescribed statins which led to finish them before next visit and experienced side effects such as headache and gastrointestinal problems are other reasons of non - adherence to statins in patients with type 2 diabetes . in spite of the importance of adherence to statin therapy for achieving therapeutic goals , there are limited reports about adherence to statin therapy and its associated factors especially in developing countries . meaningful reduction in ldl cholesterol was shown to be associated with pill count exceeding 80% . therefore , we also considered the adherence when patients took more than 80% of pills that should have been taken . however , a recent evaluation of 248 iranian patients with type 2 diabetes showed more than one - third of them were non - adherence to oral hypoglycemic agents . moreover , the overall prevalence of therapeutic noncompliance of patients with diabetes was 67.9% in saudia arabia . our results revealed that according to the pill counting , at least one fifth of patients with type 2 diabetes were nonadherent to statin treatment . in addition , both pill count and self - report agreed in defining adherent and nonadherent patients . unfortunately , there is not any database for medications in community pharmacies which demonstrates adherence in iran so we considered pill counting and self - reporting to evaluate that . other reports showed different range of adherence to statin therapy which may be related to study population , setting and method of adherence measurement . in these studies , more than 60% of patients had good adherence to statin therapy especially during the 1 month of treatment . a meta - analysis in 2012 showed 49.0% and 90.3% of patients were adherent to statins in observational and randomized studies respectively after 1-year follow - up . in comparison to conducted studies , relatively high level of adherence reported by patients in our study . this comparison is not rational because of heterogeneities of study population and method of adherence assessment between studies . in addition , pills may be lost or stolen rather than taken which can affect pill count and consequently adherence measurement . however , pill count and self - report have some limitations that cause overestimation of adherence but significance of this result is that we could find a significant relationship between adherence measured by pill counting and ldl goal attainment . small percentage of our study population had reached ldl cholesterol < 100 mg / dl ( 31.6% ) . it is similar to conducted studies reported overall 32 - 44% of patients with diabetes and dyslipidemia attained their ldl cholesterol level < 100 mg / dl . these findings show that in spite of the importance of statin therapy to decrease risk of chd , the major proportion of patients receiving statin therapy did not achieve ldl cholesterol goal . it seems inadequate adherence to statin therapy yet remains the main reason of this failure in developing and also developed countries . poly - pharmacy is common among patients with type 2 diabetes which implies to the prescription of oral hypoglycemic , antihypertensive and lipid - lowering medications for an individual . it is also a growing barrier to adherence and attainment of therapeutic goal . in a similar manner , in our study nonadherent patients had more prescribed medications . in addition , limited time spent during office or clinic visits contributes to inadequate attention to multiple aspects of this care . it is necessary to increase awareness of the most important causes of non - adherence and find solutions to improve adherence . forgetting is one of the most frequent causes of non - adherence in patients with diabetes which also reported in our study , inasmuch as it has also been mentioned a barrier to insulin injection especially in patients with type 2 diabetes . therefore the development of interventions such as using daily pill box or filling log books of daily medication use may be useful to improve adherence . another previous study also demonstrated an improvement of adherence and related outcomes in patients with type 2 diabetes by involving a pharmacist in the multidisciplinary team . however , more studies will be needed to evaluate the effects of different interventions on adherence . in addition , patient education and better interactions of patient and health care team will have the enormous effect on improving medication adherence . although because of our local culture , we could not evaluate this factor but a recent cohort study showed a decrease in adherence with decreasing income in patients with established cardiovascular disease especially among men aged 40 - 64 years . therefore , other studies will be needed to focus on other risk indicators associated with non - adherence to statin medications with diabetes especially in developing countries . there is controversy that increased medication adherence is associated with reduced healthcare expenses particularly during the years immediately following the onset of diabetes . adherence measurement , by using pharmacy record data about refilling prescription , may be easier and more precise than pill counting . therefore the development of these systems is necessary in different setting of health care system . finally , it should be mentioned pill count can be used to identify patients who are nonadherent to statin therapy and at high risk for failure to achieve ldl cholesterol goals . non - adherence to statins seems to be a significant issue in health care system for diabetic patients in iran . emphasis should be put on health care delivery systems and policy organizations to improve health care providers and patient alliance and promote clinical programs to enhance medication adherence . finding novel methods to improve adherence has giant potential to improve health outcomes and potentially decline health care costs . according to most probable barriers to adherence in our study , patient education and using pill boxes to decrease forgetting to take medication seems to be useful to increase adherence . all authors contributed for the design , data collection , data analysis and manuscript preparation .
background : despite the importance of patients adherence to their drug treatments for achieving desired therapeutic goals and the proven role 3-hydroxy-3-methylglutaryl coenzyme a inhibitors ( statins ) for the health status of patients with cardiovascular diseases , there is not enough information regarding diabetic patients adherence to statin therapy in developing countries . in this clinical study 
 we aimed to assess the adherence of diabetes type 2 patients to statin therapy in a research based community clinic in iran.materials and methods : in this prospective clinical study which was done at isfahan endocrinology and metabolism research center , 204 diabetic type 2 patients under treatment with statin were interviewed twice and their demographic data ( age , gender , body mass index , education ) , statin information ( type , dose ) and their serum lipid profile were recorded . 
 three months after the initial visits , patients were assessed using pill counting method and according to patients self - reporting and also assessed low - density lipoprotein ( ldl ) cholesterol goal attainment < 100 mg / dl.results : adherence rate was 79.7% and 69% according to pill counting and self - reporting among study population . moreover , 68.4% of patients achieved their ldl cholesterol goal of < 100 mg / dl and adherent patients reached therapeutic goal significantly more than those who were considered non - adherence to statin therapy ( p < 0.01).conclusion : adherence to statin therapy , as reflected by pill count method , is significantly related to ldl cholesterol goal achievement in patients with diabetes and dyslipidemia . 
 pill count method can be used to identify patients who are nonadherent to statin therapy and at high risk for failure to attain ldl cholesterol goals .