briefly , we retrospectively reviewed adult mdr tb and xdr tb patients admitted during 20032008 for treatment initiation to king george v hospital ( kgvh ) , a public tb - referral hospital in kwazulu - natal .
admitting physicians and staff collected data routinely . during the study period , kgvh was the only public hospital in the province authorized to initiate treatment for mdr tb and xdr tb , and all therapy was initiated on an inpatient basis .
all patients > 18 years of age who had culture - confirmed mdr tb or xdr tb with standard drug susceptibility testing were included .
ethics review committees at the university of kwazulu - natal and boston university ( boston , ma , usa ) approved the study protocol .
univariate and multivariate logistic regression models were used to estimate odds ratios ( ors ) and 95% confidence intervals ( cis ) .
statistically significant variables or variables that caused > 10% change in the univariate or were included in the multivariate model .
a total of 4,941 patients with mdr tb or xdr tb from throughout kwazulu - natal were admitted for initiation of drug - resistant tb treatment to kgvh during the study period ( figure ) . among 4,514 eligible patients with mdr tb or xdr tb , women
were younger ( median age [ interquartile range ] 32 [ 2639 ] vs. 36 [ 3044 ] years ) , more likely to be hiv infected ( 65% vs. 47% ) , and more likely than men to be receiving antiretroviral therapy ( art ) ( 51% vs. 43% ) ( table 1 ) .
women with drug - resistant tb were more likely than men with drug - resistant tb to have xdr tb ( p<0.0001 ) .
flow diagram for patients with multidrug - resistant ( mdr ) and extensively drug - resistant ( xdr ) tuberculosis ( tb ) admitted to king george v hospital , kwazulu - natal , south africa , 20032008 .
* mdr , multidrug - resistant ; tb , tuberculosis ; xdr , extensively drug - resistant ; art , antiretroviral therapy . 
median patient age ( interquartile range ) : women , 32 y ( 2639 y ) ; men , 36 y ( 3044 y ) ; p<0.0001 . 
on univariate analysis , hiv status , art ( among hiv - infected ) , female gender , previous tb treatment , and year of admission to kgvh were significantly associated with xdr tb ( table 2 ) . on multivariate analysis ,
only female gender ( or 1.38 , 95% ci 1.111.73 ) , previous tb treatment ( or 2.16 , 95% ci 1.094.28 ) , and year of admission were independently associated with xdr tb . in the hiv strata ,
art was not significantly associated with xdr tb after adjustment was made for confounding variables .
confounding of art and xdr tb by year of admission among hiv co - infected persons most likely resulted from increased xdr tb case finding after a highly publicized xdr tb outbreak in 2006 and increased art use after public health rollout of art in kwazulu - natal in 2004 . the interaction terms hiv  gender , gender  age ( categorical ) , and health care worker ( hcw )  gender were not significantly associated with xdr tb .
* xdr , extensively drug - resistant ; tb , tuberculosis ; mdr , multidrug - resistant ; or , odds ratio ; ci , confidence interval ; art , antiretroviral therapy . 
median age ( interquartile range ) : mdr tb patients 34 y ( 2842 y ) ; xdr tb patients , 35 y ( 2942 y ) . 
most ( 59% ) patients admitted with xdr tb were women , which did not change significantly during the study period ( test for trend p = 0.68 ) .
for mdr tb , the data showed increasingly more female mdr tb patients admitted over the study period ( p<0.001 ) ( table a1 ) .
our major finding was that women admitted with drug - resistant tb to kgvh were 38% more likely than men to have xdr tb .
temporal analysis showed persistently more women with xdr tb and increasing proportions of women with mdr tb during the study period .
together these data support the notion that the epidemic of drug - resistant tb predominantly affects women in kwazulu - natal . supporting context comes from observational studies of drug - resistant tb in south africa . in south african studies , higher percentages of xdr
tb ( 50%56% ) than mdr tb patients ( 43%53% ) are women ( 69 ) .
however , studies from low - prevalence hiv settings report fewer women with drug - resistant tb . in a study in the united states ,
few patients with mdr tb ( 36% ) or xdr tb ( 38% ) were female ( 11 ) .
similarly , in cohorts from latvia , peru , and russia , lower percentages of patients with mdr tb ( 17%40% ) and xdr tb ( 29%35% ) were female ( 1214 ) .
gender differences in drug - resistant tb in areas of hiv endemicity and low prevalence suggest a possible effect of the aids epidemic on prevalence of drug - resistant tb in women .
women with xdr tb might have been preferentially referred compared with men with xdr tb , women with mdr tb , or both .
we lacked data on hiv factors , such as cd4 t - cell counts , art adherence , and viral load .
similarly , we lacked data on previous tb treatment , medications , adherence , and outcome .
finally , as a hospital - based retrospective study , factors associated with survival to hospital admission , decisions to seek care , and referral patterns may introduce bias .
for example , women with drug - resistant tb may be more adherent to art , leading to improved survival , and therefore increased time for xdr tb to develop .
factors associated with secondary development of xdr tb , such as tb medication adherence or previous mdr tb treatment , could explain the association between xdr tb and female gender ( 15 ) .
factors associated with exposure to drug - resistant tb strains , including location and duration of exposure , could explain the association of xdr tb and female gender .
for example , women are more likely to participate in formal and informal care work , with potential exposure to drug - resistant tb strains , and therefore primary xdr tb might be more likely to develop ( 5 ) . these results may have major policy implications for tb control in kwazulu - natal and south africa . because women are more likely to have xdr tb in kwazulu - natal , efforts should be made to develop gender - sensitive interventions to improve diagnosis , treatment , and prevention for drug - resistant tb and hiv .
decentralization of drug - resistant tb treatment may better accommodate women in conjunction with their work , family , and child - rearing responsibilities .
further studies are needed to confirm the magnitude and determinants of the association between female gender and xdr tb .
 to determine whether women in kwazulu - natal , south africa , with drug - resistant tuberculosis ( tb ) were more likely than men to have extensively drug - resistant tb , we reviewed 4,514 adults admitted during 20032008 for drug - resistant tb . 
 female sex independently predicted extensively drug - resistant tb , even after we controlled for hiv infection . 
 this association needs further study . 