atrial fibrillation ( af ) is the most frequent chronic arrhythmia in the elderly , affecting up to 10% of the population aged 80 and above . with the population aging , the burden of af is expected to double over the next two generations , making this arrhythmia an increasingly important public health issue [ 14 ] . the risk of thromboembolic complications ( stroke and systemic embolism ) is high in af , with the relative risk of ischemic stroke being evaluated to about five in af without mitral valvular disease . the indication of anticoagulation therapy with antivitamin k ( avk ) for the prevention of thromboembolism in patients with af is based on information derived from numerous well - designed and randomized control trials [ 6 , 7 ] . numerous studies have notably shown that long term anticoagulation treatment with avk reduces the risk of ischemic stroke in patients with nonvalvular af by about 68% [ 8 , 9 ] . as a comparison , this reduction is only 22% for acetylsalicylic acid ( asa ) at preventive doses ( 75 to 325  mg / day ) [ 10 , 11 ] , with a hemorrhagic risk that is otherwise not lower than the one for avk [ 12 , 13 ] . in spite of current evidence of the benefits of anticoagulation therapy for af in patients with moderate to high cha2ds2-vasc risk scores [ 14 , 15 ] , avk is underprescribed as highlighted in this study of the elderly ( from here on defined as corresponding to the age of 75 and above ) . while 50 to 60% of geriatric patients with af should be treated with an avk , only 15 to 44% are actually treated with it [ 1618 ] . the studies evaluating possible hurdles to the prescription of avk reveal three distinct types of obstacles : patient- , physician- , and health care system - related factors . physician - related difficulties reflect their misconception of the risk / benefit ratio of administering oral anticoagulation therapy . within this category , first , the personal experience of the prescriber such as a negative event with a patient ( major gastrointestinal or cerebral bleeding ) might discourage the prescription of avk . some psychosocial factors may discourage the prescription of anticoagulants because of the concern of a higher risk of hemorrhagic complications   due to poor compliance . these factors are related to drug or alcohol abuse , psychiatric pathologies ( schizophrenia , psychosis , major depression , etc . ) , underprivileged situations ( patient isolated or without a fixed domicile ) and/or a history of noncompliance . other determining patients ' attributes are the particulars of the geriatric patient , aged 75 , and the specific risk of a potential fall , unjustifiably discouraging the prescription of avk [ 16 , 2022 ] , or inciting to target inr ( international normalized ratio ) levels that are below 2.0 [ 16 , 20 ] . the third element of the misperception of the risk versus benefit ratio of avk experienced by the prescriber is the constraints ( inr control ) and contingencies ( food interactions , bleeding risk ) of oral anticoagulation therapy [ 23 , 24 ] and the complexity of keeping inr within the therapeutic range ( 2.0 - 3.0 ) [ 16 , 18 , 24 , 25 ] . according to available data , inr remains within this range only 40 to 58% of time [ 26 , 27 ] . the recipient 's perception of the benefit versus risk ratio of avk therapy also influences the agreement to submit to anticoagulation therapy . one study reported that among those patients treated with avk for af , 48% did not understand the purpose of the treatment and 37% were not aware of their own risks of stroke . the information provided to the patient also influences patient 's decision to accept an avk treatment . another study reported that the percentage of patients accepting avk treatments varied between 30 and 87% , depending on the prescriber and the way he delivered such information about the treatment . in general , patients appear to accept a lower benefit / risk ratio than the prescribers do [ 30 , 31 ] . finally , some health care system - related factors have also been identified as hindering avk prescription in af ; one example refers to the availability of a nearby laboratory for inr measurements . it should be further investigated whether some geriatric characteristics or geriatric score could be predictive of the decision of the prescriber for anticoagulation in af in the elderly . one study   compared some geriatric attributes of patients with af who were given anticoagulants with those with af who were not . this study was retroactive and was achieved in the geriatric unit of a general hospital . the following parameters were evaluated : chads2 score , katz score , lawton scores ( daily life activity ) , and various geriatric characteristics ( cognitive , nutrition and mood status , and risk of fall ) . no difference could be observed between the two patients groups . here , we suggest searching again for such predictive geriatric characteristics in patients 75 years old , this time in a prospective way , within the context of an emergency room while increasing the number of features to be investigated . the aim of this study was to observe the prevalence of ( nonvalvular ) af in consecutive geriatric patients admitted in an emergency room and to analyze the variables associated with such underprescription of anticoagulation therapy in patients with af . consecutive eligible patients were assessed by the team in the emergency room under the supervision of one physician ( first author ) . all consecutive patients 75 years old admitted between 27 may 2011 and 23 december 2012 in the emergency unit were assessed for the presence of ( nonvalvular ) af . the total number of admitted patients as well as the number of the patients with af was collected during the length of the study . comprehensive assessment covered only those patients with af irrespective of the presence or not of avk ( or low molecular weight heparin ) therapy . patients who were not able to answer the questionnaires of the comprehensive assessment were excluded and their number collated . exclusion criteria were the following : language other than french , english or dutch , aphasia , critical condition , and/or obvious cognitive disorders . the following items were systematically gathered and recorded.the cause of admission ( general status alteration , fall , confusion , traumatism , dyspnea , precordium pain , stroke suspicion , pyrexia , and other).a social evaluation stating the age , residency status ( private home versus institution ) , living situation ( alone or not ) , and presence ( or absence ) of a followup by a general practitioner.the patient 's medical history , with a special emphasis on previous history of stroke or transitory ischemic attack ( tia).the medical treatment ( drugs administrated to the patient before admission ) , with special attention to avk therapy.the risk of an embolic stroke and related level of indication for anticoagulation therapy according to the chads2 score .the frailty of the patient , using the tool for identification of senior at risk ( isar ) .the level of daily activities ( adl ) using the lawton 's scales , with special focus on the ability to manage medications.the determination whether the patient had previous incidences of falling ( 1 fall within the 6 months before admission : named  faller  ) or not.the probability of depression using the geriatric depression scale ( gds ) .the nutritional status using the malnutrition universal screening tool ( must ) .a polypathology and severity of the medical problems using the charlson 's comorbidity index .the determination of the levels of serum urea , creatinine , albumin , and inr.the dispatch of the patients were recorded ( hospitalization or not ) . the use of the cha2ds2-vasc instead of the chads2 score would not have significantly changed the proportion of patients eligible for an anticoagulation therapy in our patient sample . we also choose not to determine the has - bled score , because this score is hardly , if ever , used by general practitioners in our country ; moreover , several criteria of this score ( hypertension , stroke , and age ) are also included in the chads2 score and some ( renal insufficiency , drugs ) do not show any contraindication for avk treatment . the cause of admission ( general status alteration , fall , confusion , traumatism , dyspnea , precordium pain , stroke suspicion , pyrexia , and other ) . a social evaluation stating the age , residency status ( private home versus institution ) , living situation ( alone or not ) , and presence ( or absence ) of a followup by a general practitioner . the patient 's medical history , with a special emphasis on previous history of stroke or transitory ischemic attack ( tia ) . the medical treatment ( drugs administrated to the patient before admission ) , with special attention to avk therapy . the risk of an embolic stroke and related level of indication for anticoagulation therapy according to the chads2 score . the frailty of the patient , using the tool for identification of senior at risk ( isar ) . the level of daily activities ( adl ) using the lawton 's scales , with special focus on the ability to manage medications . the determination whether the patient had previous incidences of falling ( 1 fall within the 6 months before admission : named  faller  ) or not . the nutritional status using the malnutrition universal screening tool ( must ) . a polypathology and severity of the medical problems using the charlson 's comorbidity index . the determination of the levels of serum urea , creatinine , albumin , and inr . all the research for this study met the criteria of the routine good clinical practices . results were collected in a database on microsoft 's excel and statistical analyses were performed using stata 11.2 software ( lakeway drive , texas , united states ) . . unpaired student 's t - test , comparing means and squared chi , was used to assess between group differences in proportion of variables . univariate and multivariate logistic regression analyses were achieved in order to identify the variables that are associated with the anticoagulated status . between may 27th 2011 and december 23rd 2011 , 1204 patients 75 years old were admitted at the emergency unit . among those patients , 92 presented exclusion criteria and 117 were excluded because data collected was incomplete . among the 995 retained patients , 142 presented with atrial fibrillation ( 14% ) . table 1 illustrates the characteristics of this group . among patients with af for whom anticoagulation was recommended ( 73% of all patients ) , only 61% actually received anticoagulation therapy . the main cause of their admission at the emergency room was  a deterioration of general status . four percent of the patients were admitted for suspicion of a stroke and/or transient ischemic attack ( tia ) . none of those patients revealed a cerebral hemorrhage by brain ct - scan , and only 1 of those patients received avk therapy ( inr of 2.4 at the time of his admission ) . among those patients admitted after trauma ( with or without a fall ) and those admitted after a fall ( 30 patients , 15 receiving avk therapy ) this last patient had not received any avk or aspirin therapy before admission . in order to analyze geriatric characteristics potentially associated with the underprescription of avk in af , we compared geriatric characteristics , comorbidities , isar score , and drug treatment between patients receiving anticoagulation therapy and patient not receiving that therapy ( table 2 ) : higher proportions of patients with recent ( 6 months ) hospitalization , comedication with digoxin , and taking > 3 different drugs were observed in the group receiving anticoagulation therapy than in the group not receiving it . all other parameters were not significantly different between these two groups . comparing the percentages of patients receiving anticoagulation therapy according to the presence of digoxin in the admission treatment , we observed that 85% of the patients receiving this drug also received anticoagulation therapy , while only 55% of the patients without digoxin treatment received it ( p < 0.003 ) . in univariate analysis , no geriatric characteristic was associated with the presence ( or the absence ) of anticoagulation therapy ( table 3 ) . in multivariate analysis , only the presence of previous hospitalization within the last 6 months and the presence of digoxin treatment were factors associated with anticoagulation therapy ( table 4 ) . the goodness - of - fit of this model remains significative , suggesting that those two factors were probably confounding . to the best of our knowledge , the present study is the first of its kind to address the issue of the variables associated with the underprescription of avk in af in the elderly , in a prospective way and in an emergency service . out of a total of 995 geriatric subjects , to begin , it concerned only a relatively small number of subjects in the context of their admission in the emergency service of a single , general , hospital that is situated in a neighborhood with a relatively high standard of living and where most patients have a suitable followup by their general practitioner . secondly , the use of a questionnaire excluded patients with cognitive impairment ( > 4% of patients in the present study ) . note that one can not exclude that , in this study , slight confusion may have not been identified and may have been ascribed as  general status alteration .  also , as the collected data is quite subjective , the patient 's answers might have been influenced by the attitude of the researcher . finally , inclusion criteria could overestimate or underestimate the accurate proportion of patients with af and known as such by their general practitioner . in our study , cases of paroxysmal af ( which nevertheless need anticoagulation ) could not be detected in the emergency room and some detected cases of af might have been de novo or hitherto unknown paroxysmal af . among all of the criteria analyzed in search of characteristics segregating patients who were anticoagulated from patients who were not , the first one is the condition of hospitalization within the 6 months that precede admission in the emergency room . indeed , the proportion of anticoagulated patients is significantly higher in those who meet this criteria ( 52% versus 33% ) . a possible explanation is that hospitalization ( whatever the reason ) constitutes a prolonged period of medical observation which allows the detection of af , including paroxysmal forms and the possibility to initiate anticoagulation in an easier way than in ambulatory practice . patients who were treated with this molecule were more often anticoagulated than subjects who were not ( 85% versus 55% ) . a possible explanation is that prescription of digoxin by the general practitioner attests his knowledge of the af and/or of a closer monitoring of the patient . the third criterion is treatment with > 3 different medications , with more such patients being anticoagulated ( 100% versus 89% ) . as for the digoxin , this could reflect closer monitoring by the physician . on the basis of the referenced scores and scales , it was not possible to identify clearly any geriatric characteristic that could be associated with underprescription of avk in af . , no geriatric characteristic seems predictive of the decision by the physician to prescribe or not to prescribe anticoagulation in af in the elderly . it can however not be excluded that such characteristic might be identified in a larger study . in the present study , 61% of patients with af were anticoagulated , which is a higher share than the about 40% generally reported in medical literature [ 1618 ] . a potential reason is the very large proportion of subjects included in the study ( 99% ) which are monitored by a general practitioner . on the basis of the chads2 score alone , 73% of the patients with af should have been anticoagulated ( score  2 ) . only 22% of anticoagulated patients had an inr between 2 and 3 , which is much lower than the amount of 40 to 58% generally reported in literature [ 26 , 27 ] . the enrollment of subjects in an emergency room ( possibly unstable situation ) may have underestimated the proportion of therapeutic inr in a stable situation . of the 15 anticoagulated patients who were admitted for a trauma or a fall , no severe hemorrhage was diagnosed , even in patients with inr > 3 at the time of admission . some observations may be made about comorbidities and comedications : 33% of patients with af had heart failure and 60% had hypertension . 18% of patients with af had previous history of stroke or tia . in our subject pool , however , this previous history did not appear to influence the decision of the physician to prescribe anticoagulation . this is in concordance with literature data on the influence of previous history of stroke on physician 's decision to prescribe anticoagulation , with only the hemorrhagic type being known to exert an influence , by discouraging the prescription . on the other hand , polymedication was systematic in our group of anticoagulated subjects : they all took at least 3 different medications , with an average of 7 . we have to recognize two limitations of our study that were due to the methodology used . firstly , by excluding patients not able to answer the questionnaires of the comprehensive assessment , we could n't study the impact of cognitive disorders . secondly , the recruitment in an emergency service required the use of a geriatric assessment that is less exhaustive than the classical  comprehensive geriatric assessment . from this study of consecutive 75 years old patients with af admitted in an emergency room and able to answer a questionnaire , no specific geriatric characteristic could be identified as significantly associated with , thus possibly predictive of , underprescription of avk treatment . only very few elements that reflect the influence of the quality of the monitoring on the probability for the patient to be actually anticoagulated could be noted . in accordance with available literature data , the present study confirms the underprescription of avk in af in the elderly and the lack of consideration for the chads2 criteria . this study reports a very weak rate of inr in the therapeutic range , although with some reserves for its interpretation due to the design of study . as already suggested , underprescription of anticoagulation in patients with af is presumably due to complex interaction between patient- , physician- , and health care system - related factors , where the need , as well as the difficulty , of maintaining the inr level within the therapeutic range probably plays a major role . could the new generations of oral anticoagulant ( anti - xa and anti - ila ) change this situation is a relevant question for the future .
several studies have reported underprescription of anticoagulants in atrial fibrillation ( af ) . 
 we conducted an observational study on 142 out of a total of 995 consecutive 75 years old patients presenting af ( 14% ) when admitted in an emergency unit of a general hospital , in search of geriatric characteristics that might be associated with the underprescription of anticoagulation therapy ( mostly antivitamin k at the time of the study ) . 
 the following data was collected from patients presenting af : medical history including treatment and comorbidities , chads2 score , isar scale ( frailty ) , lawton 's scale ( adl ) , gds scale ( mood status ) , must ( nutrition ) , and blood analysis ( inr , kidney function , and albumin ) . among those patients for who anticoagulation treatment 
 was recommended ( 73% ) , only 61% were treated with it . in the group with anticoagulation therapy , the following characteristics were observed more often than in the group without such therapy : a recent ( 6 months ) hospitalization and medical treatment including digoxin or based on > 3 different drugs . 
 neither the value of the chads2 score , nor the geriatric characteristics could be correlated with the presence or the absence of an anticoagulation therapy . 
 more research is thus required to identify and clarify the relative importance of patient- , physician- , and health care system - related hurdles for the prescription of oral anticoagulation therapy in older patients with af .