despite the directly observed treatment short course ( dots ) strategy , tuberculosis ( tb ) is still a major public health problem in the world ( 1 ) . according to the world health organization ( who ) , about 8 to 8 million people annually are diagnosed with tb ,
diabetes is a debilitating disease that impairs the cellular immune system and provides the ground for tb . the who estimates that by 2030 , the population of diabetics is increasing and reaches about 316 million people , most of them are living in developing countries ( 4 - 6 ) .
diabetes mellitus ( dm ) is a common chronic metabolic disorder that affects mainly the country 's elder population . according to the center for disease control ( cdc ) ,
the leukocyte dysfunction and reduction of serum bactericidal activity in dm patients increases the risk of tb infection ( 8 , 9 ) .
patients with dm are at increased risk of pulmonary tb ( 10 - 17 ) . knowing the epidemiological , clinical , laboratory and radiological aspects of patients with tuberculosis helps involved practitioners in rapid diagnosis and initiating appropriate treatment .
prompt and appropriate treatment is the most effective way to prevent of treatment failure , relapse , or emergence of multi drug resistant tb ( mdr - tb ) which today is the main problems in fighting against tb ( 3 ) . because the differences in the immune response in diabetics and non - diabetic infected hosts , epidemiological , clinical , radiological , laboratory tests results and response to treatment varies in these patients ( 8 , 9 ) .  
tuberculosis in older people with weak immunity is associated with less cough and fever in compare with younger individuals while , pleural effusion and cavitation are more common in patients with normal immune responses ( 3 ) . to the best our knowledge ,
such study in diabetic patients with pulmonary tuberculosis has not been performed in khuzestan - a province with a population of over 4.5 million .
since the majority of deaths in patients with pulmonary tuberculosis occur in hospitalized patients , thus , hospital - based studies provide useful information on various aspects of the disease .
considering that knowing this information is necessary to control tb , this study aimed to compare the epidemiological characteristics , clinical , laboratory and radiological findings in patients with pulmonary tb in diabetic and non - diabetic patients .
in this retrospective study , all cases of pulmonary tb , hospitalized in razi hospital during two years ( 2009 and 2010 ) were reviewed . to find more information , complete data and matching the data with health file of patients , tb documents in khuzestan health center
razi hospital in ahvaz is the referral center for almost all cases of pulmonary tb , therefore , we assumed the above cases as s representative of all tb cases in khuzestan .
patients data on demographics , residential area , habits , past medical history , laboratory and sputum microscopy analysis , as well as clinical signs and symptoms , radiological findings , the patient 's condition of diabetes ( self - referred , under treatment of oral anti - diabetic medication and fasting blood sugar levels ) , receiving anti - tb drugs , tb treatment response and other relevant information were extracted from patient records .
patients were divided into two groups ; a group of patients with pulmonary tuberculosis and with diabetes mellitus called as dm & ptb , and other group of patients with pulmonary tuberculosis but without diabetes mellitus called as non - dm & ptb .
study inclusion criteria were as follow : patients who had pulmonary tuberculosis , based upon the national anti - tb program ( ntp ) .
pulmonary tb : at least two tests of positive sputum smear acid - fast test or one positive sputum smear acid - fast and a chest radiograph consistent with tb , smear - negative pulmonary tuberculosis ; at least 3 sputum tests negative for acid - fast bacilli ( afb ) but positive radiographic or a doctor 's decision on anti - tb treatment in the presence of clinical signs and symptoms consistent with tb and age older than 15 years . in additions , the exclusion criteria were cases with no state of sputum smear analysis , cases with incomplete information and non - diabetic patients but , with other underlying diseases that may influence the immune status .
patient 's data in both groups were analyzed in spss-16 using chi - square test and fisher exact tests .
from 169 cases of ptb , 5 patients were excluded due to incomplete data , 8 due to defects in the state of sputum smear results , and 8 due to hiv infection . of the remaining 148 patients , 36 patients had diabetes mellitus .
mean age in the dm & ptb and non - dm & ptb group were ( n = 36 ) , 56.6  12.7 ( n = 112 ) was 44.8  18.3 years , respectively . as shown in table 1 , prevalence of pulmonary tuberculosis among older than 60-years diabetic patients have no significant difference with those below 60 years of age , whereas , the mean age in diabetic 's cases was higher than in non - diabetics . although more males than females are diagnosed with ptb , but this difference was not significant . also , while tb prevalence is higher in urban areas than in rural ones , he difference is not significant .
clinical signs and symptoms in both groups are shown in table 2 . although symptoms such as cough , night sweat , fever , and weight loss in both groups exist , but , sputum production , hemoptysis , and dyspnea in patients with diabetes were more prevalent than in non - diabetic patients .
radiological features in non - diabetic and diabetic patients are shown in table 3 .  
statistically significant   abbreviations : dm & ptb , diabetes mellitus and with pulmonary tuberculosis   data are presented as no .
( % )   statistically significant there is a similar frequency of infiltration and upper lobe opacity in both groups , but there is a higher frequency of the cavity lesions and reticulunodular pattern in diabetic patients comparing with non - diabetic patients . in diabetic and non - diabetic patients , cell blood count ( cbc ) was normal ( normal range : 7000 - 10000 ) in 108 patients ( 96.4% ) , 31 patients ( 86.1% ) , which was not statistically significant ( p > 0.05 ) .
mean value of erythrocyte sedimentation rate ( esr ) in diabetic and non - diabetic patients were respectively 49.6 and 53.3 mm / h , which was not statistically significant ( p > 0.05 ) . in diabetic patients ,
sputum smear was positive for afb in 24 ( 66.6% ) patients , while in non - diabetic patients it was positive in 53 ( 47.3% ) patients , which was statistically significant ( p = 0.03 ) .
number of mdr - tb in the non - diabetic group was 2 , and in diabetic group was 4 , although statistically was not comparable , but regarding to the country rate and expected rate in ntp ( 2% ) and percent in these patients ( 5.5% vs. 3.5% ) is considerable .
although some epidemiological features of pulmonary tuberculosis such as gender , age and residential area are similar in both diabetic and non - diabetic patients , but in clinical point of view , radiological and laboratory features were more dominant in diabetic pulmonary tuberculosis - infected patients comparing with non - diabetics patients . in dealing with patients suspected of having tb , these differences should be considered .
these results are consistent with other studies ( 10 , 11 , 15 - 19 ) .
although , the incidence of tb in people over 60 years and under 60 years showed no significant difference ; however , the mean age of patients with pulmonary tuberculosis in diabetic patients was higher than non - diabetic patients .
this is justified because , firstly , old tb infected persons are at in increased risk of tb reactivation ; secondly , the incidence of diabetes is higher in the older age .  
we can not easily say that the incidence of tuberculosis in elderly diabetics is higher than aged non - diabetics . to demonstrate this
, we first need to compare non - tb diabetic and non - diabetic cases for age .
( 18 ) in their study in masih daneshvari hospital ( the country 's referral center ) in tehran , iran , showed that the mean age of diabetic patients with pulmonary tuberculosis is a little more than non - diabetic tb patients ( 57.8 vs 55.2 years ) .
have also shown that the mean age of tb patients with diabetes is higher than non - diabetic tb patients ( 11 ) .
this study shows that patients in rural area have higher prevalence of diabetes and tb comparing to rural areas .
suburbs , where people live in crowd environments greater chance of exposure to infectious tb patients may causes great number of afb in the air .
because of the limited studies in this field , comparing the results of this study with other studies in other areas of the country is not possible .
stevenson et al . , has also pointed out a higher incidence of pulmonary tuberculosis in diabetic patients in urban areas than in rural areas ( 15 ) .
the present study revealed that cough , fever and night sweats in diabetic patients are the same in non - diabetic patients , but the sputum production , hemoptysis , and dyspnea are observed in the diabetics more frequent than in non - diabetics .
has demonstrated that anorexia , dyspnea and hemoptysis in diabetes were higher than in non - diabetes but , cough and sputum production in both groups were similar ( 18 ) . in general , the results of the clinical findings in this study are concordant to the results of other studies conducted in other regions ( 15 , 17 ) .
it seems that diabetes mellitus patients , because of diabetes - induced immunodeficiency , are incapable of inhibiting the progression to disease , therefore , disease progress more rapidly and the blood vessel wall and pleural involvement results in hemoptysis and dyspnea .  
these results are in agreement with previous studies in medical literature ( 3 , 10 , 11 , 13 , 17 ) . in this
study the radiographic findings , such as upper lobe opacities and pleural effusions , are similar in both groups , but cavitation and nodular infiltration ( miliary mottling ) pattern are more observed in diabetic compared with non - diabetic patients ( 3 ) . regarding the fact that the inflammatory response is suppressed in immunocopromised host , frequency of cavitary lesions in non - diabetic individuals with normal immunity is conceivable .
however miliary pattern in patients with diabetes can be explained for of the spread of disease because of cellular immunity impairment .
however , because the study was retrospective , it is not clear exactly how their diabetes was controlled and how they were their immune status .  
future studies are needed to clarify this issue with the substantial sample size and the level of cellular immunity . except in baghaei
et al study ( 18 ) with similar radiological findings in both groups ( except in cavitation ) , no other studies were found regarding this issue , addressing our country .
they reported that diabetic patients had a higher prevalence of typical presentations along with cavitary lesions ( 18 ) .
but in the studies of other countries , the prevalence of cavities in chest radiography of diabetic patients with pulmonary tuberculosis has been suggested ( 10 , 11 , 17 ) .   in this study ,
in other words , the chances of isolating the tuberculosis bacillus in the sputum of diabetic tb patients are more than non - diabetic patients .
these findings are in agreement with other studies in this subject ( 15 ) , because these patients are associated with increased sputum production , and also because of more cavitation and tissue immune inhibition , the possibility of access to further sputum containing bacilli exist . in stevenson
study , higher rates of sputum positivity have been reported in diabetic patients ( 15 ) .
in other comorbidities , such as the elderly or patients with advanced aids , tuberculosis bacillus isolation level is higher than tuberculosis patients with normal immunity ( 3 ) . in this study , based on limited number of drug resistance cases ,
multidrug - resistant tb cases can not be discussed , however , the increasing number of patients with mdr - tb ( comparing with ntp limit ) has alarmed in diabetes and further prospective studies in this field is recommended .
bashar et al . , has also warned the importance of mdr - tb among diabetic individuals ( 16 ) .   to the best our knowledge ,
till now , there is no similar study in the province , and studies in this field in iran are very limited , so this study can be considered as a new work .
the study design is retrospective and is limited to only one hospital . since our hospital is the only referral infectious diseases center in ahvaz , this limitation can be justified .
future population - based studies are needed to generalize these results to the whole community in the region .
epidemiology of tuberculosis in both diabetic and non - diabetic patients is similar . although the signs and symptoms of tb disease in diabetic patients are the same with non - diabetic ones , but sputum production , hemoptysis , and dyspnea are more prevalent in diabetics .
chest radiography in diabetic patients is a useful diagnostic modality for detecting advanced lesions such as cavity and miliary lesions . according to the results of this study , in approach to every dm case presenting with respiratory symptoms such as productive cough , hemoptysis and dyspnea in association with cavitation or reticulonodular pattern in chest x - ray
to the best our knowledge , till now , there is no similar study in the province , and studies in this field in iran are very limited , so this study can be considered as a new work .
the study design is retrospective and is limited to only one hospital . since our hospital is the only referral infectious diseases center in ahvaz , this limitation can be justified .
future population - based studies are needed to generalize these results to the whole community in the region .
epidemiology of tuberculosis in both diabetic and non - diabetic patients is similar . although the signs and symptoms of tb disease in diabetic patients are the same with non - diabetic ones , but sputum production , hemoptysis , and dyspnea are more prevalent in diabetics .
chest radiography in diabetic patients is a useful diagnostic modality for detecting advanced lesions such as cavity and miliary lesions . according to the results of this study , in approach to every dm case presenting with respiratory symptoms such as productive cough , hemoptysis and dyspnea in association with cavitation or reticulonodular pattern in chest x - ray
 background : diabetes mellitus ( dm ) due to suppressive effect on cellular immunity can impact on progression of tuberculosis ( tb).objectives : the aim of this study was to investigate the impact of dm on the epidemiological , clinical and para clinical aspects of pulmonary tb.patients and methods : the information of 148 admitted pulmonary tb patients in infectious ward of razi hospital in ahvaz from 2009 to 2010 was extracted from their medical files . 
 the patients were divided into two groups as tb with dm ( n = 36 ) and tb without dm ( n = 112 ) . 
 the related data on epidemiology , signs , symptoms , radiology and sputum smear examination in both groups were compared in spss 16 by using chi squared test.results:the mean age of tb with dm patients was higher tb without dm patients ( 56.6  12.7 vs. 44.8  18.3 ; respectively , p = 0.006 ) . whereas cough , night sweating , fever and 
 weigh loss was not statistically different , sputum , hemoptysis and dyspnea was more prominent in tb with dm ( 69.4% , 33.4% , 44.5% vs. 36.6% , 9.8% , 20.5% ; p = 0.005 , p = 0.001 , p = 0.005 , respectively ) . in chest x - ray , cavitation and reticulonodular pattern 
 was more frequent in tb with dm ( 55.5% , 22.2% vs. 31.2% , 8% - p = 0.008 , 
 p = 0.02 , respectively ) . 
 the rate of sputum smear positivity in tb with dm and tb without dm was 66.6% and 47.3% , respectively ( p = 0.03).conclusions : according to the results of this study , in approach to every dm cases suffering of respiratory symptoms such as productive cough , hemoptysis and dyspnea in association with cavitation or miliary mottling in chest x - ray , pulmonary tb should be considered at the top of the differential diagnosis list . 
1. Background
2. Objectives
3. Patients and Methods
4. Results
5. Discussion
5.1. Study strength and limitation