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Hepatitis C testing practices and prevalence in a high-risk urban ambulatory care setting: 'prevalence 3-7 times higher than 1.6% reported by CDC'..... - pdf attached
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"risk-factor-based testing preferable...12% among African-Americans & Latinos...43% among substance abusers....3% among alcohol abusers....16% with psych illness....9% with STDs....34% among HIV+"
Journal of Viral Hepatitis, March 2011 Early View (Articles online in advance of print)
W. N. Southern,1,2,3 M.-L. Drainoni,4,5 B. D. Smith,6 C. L. Christiansen,4 D. McKee,7 A. L. Gifford,4,8,9 C. M. Weinbaum,6 D. Thompson,10 E. Koppelman,4,5 S. Maher7 and A. H. Litwin1,2 1Department of Medicine, NY, USA; 2Division of General Internal Medicine, NY, USA; 3Section of Hospital Medicine, NY, USA; 4Health and Policy Management Department, School of Public Health, Boston University, NY, USA; 5Center for Health Quality, Outcomes and Economic Research, ENRM Veterans Administration Hospital, NY, USA; 6Division of Viral Hepatitis, Centers for Disease Control and Prevention, National Center for HIV/Viral Hepatitis/STD/TB Prevention, GA, USA; 7Department of Family Medicine; Albert Einstein College of Medicine, Montefiore Medical Center, NY, USA; 8Section of General Internal Medicine, Boston University School of Medicine, NY, USA; 9VA QUERI-HIV/Hepatitis Program, Edith Nourse Rogers Memorial Veterans Hospital, NY, USA; and 10Emerging Health Information Technology, NY, USA
"we found a very high estimated prevalence of HCV infection in a high-risk urban patient population with a high prevalence of risk factors. We found strong evidence that physicians are using a risk-based screening strategy to identify patients with HCV infection, using known risk factors and other conditions associated with HCV to guide testing. We also found evidence that screening recommendations should be expanded to include the high prevalence birth cohort."
"Although testing all patients born in the high prevalence birth cohort may be warranted, evidence suggests that birth cohort-based testing alone would be a less than optimal strategy......our data suggest that birth cohort-based testing would fail to identify 26.7% of anti-HCV positive persons......several factors were independently and strongly associated with positivity after adjustment for birth-cohort status including substance abuse, HIV, cirrhosis, and ALT elevation.....in our study the risk-based screening strategy yielded high rates of anti-HCV positivity in all categories of risk in patients born outside the high-risk birth-cohort. These data suggest that current risk-based screening methods should be continued, and serious consideration should be given to expanding screening recommendations to include birth in the high-risk cohort. Birth cohort testing alone, however, is not recommended."
"Testing practices in the three clinics evaluated in this study show that physicians test patients with known risk factors to identify HCV infection. The majority of patients with substance abuse (78.1%), alcohol abuse (74.3%), HIV (87.4%), cirrhosis (89.7%), end-stage renal disease (85.1%), ALT elevation (67.2%), or STDs (52.8%) were tested. In addition, a substantial proportion of patients with psychiatric diagnosis (49.7%) were tested. Each of these factors was independently associated with testing in multivariate analysis."
"In this clinic population of an urban academic medical center, the conservative (floor) estimate of the prevalence of hepatitis C antibodies was 4.6%, almost three times the estimated national prevalence [1]. Our model designed to predict positivity in the untested population estimated a much higher overall prevalence, 7.7%, which is close to the prevalence of 8.3% reported in a similar population by McGinn [5]. Overall, 39.7% of subjects had been tested. Among those with identified risk (either born in the high prevalence birth-cohort, had a high-risk co-morbidity, or an elevated ALT level), 48.6% had been tested."
'prevalence was 11% among African-Americans & 12% among Latinos at Montefiore Hospital in the Bronx, 43% among substance abusers, 33% among alcohol abusers, 34% among HIV+, 16% among those with psych illness, 30% among those with ALT>40 U/L, 16% with any risk factor vs 3% with no risk factor, 17% among 45-54 yrs old, 20% 55-64 yrs old....'.....In multivariate analysis, each of the following factors was significantly independently associated with anti-HCV testing: born in high prevalence birth cohort; male sex; African-American race; Latino ethnicity; substance abuse; alcohol abuse; HIV; STD; cirrhosis; end-stage renal disease; psychiatric disease; and elevation of ALT......The proportion of patients tested for anti-HCV and the proportion testing positive stratified by demographics, high-risk co-morbidities, and ALT elevation are reported in Table 2. Several high risk co-morbidities were associated with a large proportion of subjects tested including substance abuse (78.1% tested, 43.8% positive), alcohol abuse (74.3% tested, 33.1% positive), HIV (87.4% tested, 34.4% positive), cirrhosis (89.7% tested, 51.7% positive), and end-stage renal disease (85.1% tested, 9.5% positive).. A substantial proportion of subjects aged 18-29 years were tested (30.3%), but a small proportion of those tested positive (0.4%).. Of subjects with any risk factor (in the high-prevalence birth cohort, any high-risk co-morbidity, or elevation of ALT), 48.6% were tested and 15.7% of those tested positive. Of subjects without any risk factor noted, 28.8% were tested, and of those, 3.0% were positive.
Summary. Approximately 3.2 million persons are chronically infected with the hepatitis C virus (HCV) in the U.S.; most are not aware of their infection. Our objectives were to examine HCV testing practices to determine which patient characteristics are associated with HCV testing and positivity, and to estimate the prevalence of HCV infection in a high-risk urban population. The study subjects were all patients included in the baseline phase of the Hepatitis C Assessment and Testing Project (HepCAT), a serial cross-sectional study of HCV screening strategies. We examined all patients with a clinic visit to Montefiore Medical Center from 1/1/08 to 2/29/08. Demographic information, laboratory data and ICD-9 diagnostic codes from 3/1/97-2/29/08 were extracted from the electronic medical record. Risk factors for HCV were defined based on birth date, ICD-9 codes and laboratory data. The prevalence of HCV infection was estimated assuming that untested subjects would test positive at the same rate as tested subjects, based on risk-factors. Of 9579 subjects examined, 3803 (39.7%) had been tested for HCV and 438 (11.5%) were positive. The overall prevalence of HCV infection was estimated to be 7.7%. Risk factors associated with being tested and anti-HCV positivity included: born in the high-prevalence birth-cohort (1945-64), substance abuse, HIV infection, alcohol abuse, diagnosis of cirrhosis, end-stage renal disease, and alanine transaminase elevation. In a high-risk urban population, a significant proportion of patients were tested for HCV and the prevalence of HCV infection was high. Physicians appear to use a risk-based screening strategy to identify HCV infection......Anti-HCV prevalence among the 3803 (39.7%) persons in this sample tested in our medical systems was 11.5%. The floor estimate of HCV prevalence for the entire study population (assuming all untested subjects are negative) was 4.6%. The ceiling estimate of HCV prevalence (assuming untested subjects would test positive at the same rate as those tested, based on risk profile) was 7.7%
INTRODUCTION
An estimated 3.2 million persons are chronically infected with the hepatitis C virus (HCV) in the U.S. [1], roughly three times as many as are infected with HIV [2]. HCV infection is thought to cause approximately 40% of chronic liver disease [3] and the majority of hepato-cellular carcinoma [4] Although the prevalence of anti-HCV is estimated at 1.6% in the U.S. [1], urban populations bear a disproportionate burden of infection and inner city prevalence has been reported as high as 8.3% [5]. Effective treatment for HCV infection is available [6-10], but the majority of those infected are not aware of their status [11-15]. Although testing for patients at high risk is recommended [3,9,10,16,17], optimal testing strategies have not been described [18]. To inform the discussion of testing strategies, we sought to examine the associations between patient characteristics and HCV testing practices among physicians, and estimate the prevalence of HCV infection in a high-risk urban population.
It has been suggested that routine testing for HCV is not efficient [17] or cost-effective [19,20]. Guidelines suggest testing patients with a history of transfusion or organ transplant prior to 1992, persons using injection drugs [3,9,16,17], those with HIV infection [3,9,10], those receiving hemodialysis [3,9,16,17], children of HCV-infected mothers, and persons with unexplained elevated alanine transaminase (ALT) levels [3,9,17]. In addition, it has been noted that prevalence of HCV infection is very high in patients with a history of alcohol abuse [21,22], sexually-transmitted diseases (STD) [23-25], and psychiatric disease [26-29]. It has also been noted that the majority of prevalent cases of HCV infection are found in patients born between 1945-1964 [1,30,31], and thus, being born in this high prevalence birth-cohort may be considered a risk factor for HCV infection.
It is unclear which of these potential risk factors physicians consider important when deciding which patients to test for HCV, and which testing strategies yield high rates of positivity. The objectives of this analysis were to examine the testing practices of physicians to determine which patient characteristics are associated with testing for HCV antibody and HCV infection, and to estimate the prevalence of HCV infection in a high-risk urban population. We hypothesized that many patient risk factors would be independently associated with HCV testing, and that the prevalence of HCV infection in this population would be significantly higher than the national prevalence.
DISCUSSION
Testing practices in the three clinics evaluated in this study show that physicians test patients with known risk factors to identify HCV infection. The majority of patients with substance abuse (78.1%), alcohol abuse (74.3%), HIV (87.4%), cirrhosis (89.7%), end-stage renal disease (85.1%), ALT elevation (67.2%), or STDs (52.8%) were tested. In addition, a substantial proportion of patients with psychiatric diagnosis (49.7%) were tested. Each of these factors was independently associated with testing in multivariate analysis.
The majority of anti-HCV positive patients identified (73.3%) were born in the high prevalence birth-cohort. Being born in these years was also independently associated with HCV testing and anti-HCV positivity in multivariate analysis. Although testing all patients born in the high prevalence birth cohort may be warranted, evidence suggests that birth cohort-based testing alone would be a less than optimal strategy. First, our data suggest that birth cohort-based testing would fail to identify 26.7% of anti-HCV positive persons, which is similar to the unidentified proportions found when testing only in the birth cohort reported by O'Brien (25.4%) [31], Armstrong (34.4%) [1], and Alter (31.3%) [30]. Second, several factors were independently and strongly associated with positivity after adjustment for birth-cohort status including substance abuse, HIV, cirrhosis, and ALT elevation. Lastly, in our study the risk-based screening strategy yielded high rates of anti-HCV positivity in all categories of risk in patients born outside the high-risk birth-cohort. These data suggest that current risk-based screening methods should be continued, and serious consideration should be given to expanding screening recommendations to include birth in the high-risk cohort. Birth cohort testing alone, however, is not recommended.
In this clinic population of an urban academic medical center, the conservative (floor) estimate of the prevalence of hepatitis C antibodies was 4.6%, almost three times the estimated national prevalence [1]. Our model designed to predict positivity in the untested population estimated a much higher overall prevalence, 7.7%, which is close to the prevalence of 8.3% reported in a similar population by McGinn [5]. Overall, 39.7% of subjects had been tested. Among those with identified risk (either born in the high prevalence birth-cohort, had a high-risk co-morbidity, or an elevated ALT level), 48.6% had been tested.
It is worth noting that the proportion tested was very high (28.8%) among patients with no identified risk (born outside the high prevalence birth-cohort, no high-risk co-morbidity, and no elevation of ALT) and that the rate of positivity in this group was substantial (3.0%), though less than those with identified risks. Whether a substantial proportion of these tested patients had risk factors not identified through the EMR is not clear. It is also possible that some patients without apparent risk were tested because patients or providers were responding to New York Department of Health efforts, begun in 2004, to raise Bronx community and provider awareness of HCV infection [39]. Because of the high underlying prevalence of HCV infection (between 4.6% and 7.7%) in this population, universal testing for high-risk urban populations may be more appropriate than the risk-based screening strategy.
This analysis has several important limitations. First, not all patients were tested for anti-HCV so the prevalence we report is an estimate based on risk profile. Second, we utilized an EMR for data collection so we were unable to capture all risks for HCV infection for each patient. Lastly, we did not take into account the temporal relationship between risk factors and HCV tests. It is possible, for example, that a substance abuse diagnosis might have been coded after a HCV test was ordered, and thus we cannot be sure that the diagnosis of substance abuse was present, or in the physician's mind, at the time of testing. Despite these limitations, we were able to uncover a strong relationship between high-risk co-morbidities and physician testing behavior.
In conclusion, we found a very high estimated prevalence of HCV infection in a high-risk urban patient population with a high prevalence of risk factors. We found strong evidence that physicians are using a risk-based screening strategy to identify patients with HCV infection, using known risk factors and other conditions associated with HCV to guide testing. We also found evidence that screening recommendations should be expanded to include the high prevalence birth cohort.
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