High HIV-TB co-infection rates in marginalized populations: evidence from Alberta in support of screening TB patients for HIV.

Long, Richard ; Boffa, Jody

As experience from HIV-endemic countries has taught us, HIV and TB go hand in hand. HIV infection is a powerful risk factor for the reactivation of latent tuberculosis infection (LTBI) and a major contributor to the global resurgence of TB. Heretofore we have not seen strong evidence of this synergy in Canada, although this may simply reflect a lack of concurrent surveillance for the two diseases. To date, the goal of universal HIV testing of TB patients in Canada remains elusive (27.2% of TB patients were reported as HIV tested in 2006) despite the existence of two national advisories, one in 1992 and another in 2002, recommending universal HIV testing of TB patients. (1-3) In response to these advisories, we recently undertook to demonstrate the feasibility of using an 'opt-out' approach to achieve universal HIV testing (>80% tested) of TB patients in Alberta. The 'opt-out' approach we used was patterned after an established program of 'opt-out' HIV testing in prenatal women. (4) It is akin to the 'provider-initiated' HIV testing program now promoted by the World Health Organization. (5,6) In it, patients are briefly informed about HIV's connection to TB and the routine testing of TB patients in Alberta for HIV unless they choose not to be tested. 'Opt-out' testing was extremely well received; by 2003 and every year thereafter, over 80% of TB patients were routinely tested for HIV. We first reported our findings in the March/April 2009 issue of the Canadian Journal of Public Health. (7) In the present commentary, we add two more years of data (20072008) to our earlier report and demonstrate for the first time that HIV co-infection is significantly greater in certain age and population groups of TB patients. Our findings underscore the need for universal concurrent testing as well as greater interaction between TB and HIV programs. (8)

In 2003-2006 and 2007-2008, respectively, the proportion of TB patients who were HIV tested in Alberta was 81.9% and 94.6%; 87.4% and 99.5% in the age group 15-64 years where all of the HIV co-infected patients were situated (Table 1). In the two time periods combined, the proportion was 86.4%; 91.8% in the age group 15-64 years. In 2003-2006 and 2007-2008, respectively, the proportion of HIV-tested patients who were HIV positive was 5.4% and 7.6%; 7.4% and 10.4% in the age group 15-64 years. In the two time periods combined, the proportion was 6.3%; 8.5% in the age group 15-64 years.

Over the two time periods combined and within the age group 15-64 years, age and population group were significant predictors of HIV co-infection (Table 2). In exact multivariate logistic regression analysis (SAS), HIV co-infection was found to be significantly higher in patients aged 35-64 years than in patients aged 15-34 years (10.2% versus 6.5%, respectively, p<0.005), and similarly in Aboriginal peoples and immigrants to Canada from sub-Saharan Africa (14.7% and 20.9%) compared to Canadian-born non-Aboriginal peoples and immigrants to Canada from other regions combined (2.9%, p<0.003 and p<0.001). Higher HIV co-infection rates in middle-aged versus young adult TB patients may reflect not only age at HIV infection but years of living with HIV (and therefore immune status) at diagnosis of TB. (9) Prevalence rates were derived from institutional databases and did not control for the determinants of health. In Canadian-born persons in particular, comorbidity differentials may relate less to being a Canadian-born Aboriginal person than to socio-economic, cultural or behavioural conditions. The generalizability of these results to other jurisdictions in Canada is not known, but is likely to be similar.

A high rate of HIV co-infection among Aboriginal TB patients aged 15-64 years, a rate that is not dissimilar (though the numbers are small) to the one we report in sub-Saharan African TB patients (p=0.25), is deeply troubling, especially in a developed country with ample resources. The steadily rising proportion of positive HIV test reports among Aboriginal persons in recent years and the data presented here suggest that HIV has the potential to further exacerbate what is already an unsatisfactory state of TB control in Aboriginal peoples. (9,10) Within Aboriginal groups, heterosexual contact and injection drug use are the main HIV exposure categories. (9) Rates of all sexually transmitted infections (STIs), including an ongoing outbreak of syphilis, are high and rising in Alberta, with disproportionately high rates among Aboriginal persons. (11) STIs, in particular ulcerative infections such as syphilis, facilitate the spread of HIV. Integrating STI treatment services into an existing health care system has been demonstrated to reduce HIV transmission, particularly in jurisdictions where STI prevalence is high but HIV prevalence is low to medium. (12) Making a timely diagnosis of HIV and providing treatment of LTBI to co-infected Aboriginal persons are a high priority.

While the increased HIV co-infection rate among the subSaharan African group is concerning, it is not as surprising. Sexual behaviour patterns are determined by cultural and socio-economic contexts. In the developing countries of sub-Saharan Africa, where heterosexual contact is the main HIV exposure category, certain of these contexts have been identified as contributing to the extensive spread of HIV. These include the subordinate position of women, impoverishment and decline of social services, rapid urbanization and modernization, and wars and conflicts. (13) According to Citizenship and Immigration Canada data, between 2002 and 2003 at least 50% of all HIV diagnoses detected among persons applying to immigrate to Canada were in individuals born in the World Health Organization's 'sub-region 1', an epidemiologic grouping of African countries with both high HIV prevalence and TB incidence. (14,15) Our findings among this population in Alberta reinforce the importance of collaboration among Citizenship and Immigration Canada, the Public Health Agency of Canada and the provinces and territories and between HIV and TB programs. HIV-infected immigrants and refugees ought to be tuberculin tested and if positive offered treatment of LTBI.

At least two criticisms of our commentary come to mind, one directed at publicizing our results, the other at universal HIV testing of TB patients. First, as has been pointed out by others, there is a danger in overemphasizing sero-prevalence research to the exclusion of studies on the social determinants of health. (16,17) Negative stereotypes end up being reinforced as does discrimination against minority groups both within and beyond their own community. (16,17) No doubt the reasons for the significantly higher co-morbidity rates in minority groups herein reported are complex and intertwined with many confounding issues (economic, historic, and social) that also disproportionately affect those groups--e.g., poverty, substance and alcohol abuse, unequal access to health care, etc. (18,19) Superimposed on these factors are the unique cultural beliefs and contexts that influence behaviour, health beliefs in general and HIV infection in particular. (16,18) This notwithstanding, there is very little if any comprehensive data on HIV co-infection of TB patients in Canada and without such data little can be expected in the way of concerted action. Second, one might question the need to HIV test TB patients outside the age group 15-64 years, no co-infection having been found in those under 15 or over 64 years of age. Here we would argue, as we did in our earlier report, that anything other than truly universal HIV testing will fail to identify some individuals who are HIV infected, that universal HIV testing does not discriminate, is less likely to be perceived as stigmatizing, and if HIV co-infection is discovered, determines the patient to have AIDS.7,20,21 Already in 2009, one child under the age of 15 has been reported to be co-infected; other jurisdictions have reported patients in the age group >64 years to be co-infected.

Alberta's experience with universal HIV testing of TB patients has proven feasible and salutary. First, it was of immediate benefit to the patients, many of whom were not known to be HIV-infected and had low CD4 cell counts. (7) Second, it reinforced the need for targeted tuberculosis preventive therapy in HIV-TB co-infected persons. Third, it identified the need for greater STI prevention and control, particularly in Aboriginal peoples, and greater emphasis on contextually and culturally appropriate HIV and AIDS prevention in both Aboriginal peoples and immigrants to Canada from sub-Saharan Africa. (22) Fourth, it added weight to the argument that all immigrants and refugees with HIV infection ought to be referred for medical surveillance for both HIV and TB as a condition of entry to Canada. (10) Currently, HIV is not under medical surveillance and TB referral is only required for patients with a history of TB or evidence of old healed TB on chest radiograph. (10) And fifth, it underscores the need for a much greater provincial/territorial and national response to what are unacceptably high rates of TB and HIV in Aboriginal peoples and the need for a strong and sustained international response to TB and HIV in developing countries, particularly those of sub-Saharan Africa.

Acknowledgements: The authors thank the staff of Provincial Program Development and Disease Control, Alberta Health and Wellness and the Edmonton and Calgary TB Clinics for their assistance in assembling the TB data; the staff of the Provincial Laboratory for Public Health for their assistance in cross-matching HIV and TB data; and Norah Landry for her assistance in preparing the manuscript. Source of funding: Supported by a grant from the University of Alberta Hospital Foundation.

Received: August 21, 2009

Accepted: February 5, 2010

REFERENCES

(1.) Tuberculosis in Canada 2006. Public Health Agency of Canada. Minister of Public Works and Government Services Canada, 2008. Available at: http://www.publichealth.gc.ca/tuberculosis (Accessed August 21, 2009).

(2.) Canadian Thoracic Society, Tuberculosis Directors of Canada, Department of National Health and Welfare in consultation with the provincial and territorial epidemiologists, AIDS coordinators and HIV caregivers. Guidelines for the identification, investigation and treatment of individuals with concomitant tuberculosis and HIV infection. CCDR 1992;18:155-60.

(3.) The Canadian Tuberculosis Committee of the Centre for Infectious Disease Prevention and Control, Population and Public Health Branch, Health Canada. Recommendations for screening and prevention of tuberculosis in patients with HIV and for screening for HIV in patients with tuberculosis and their contacts. CCDR 2002;28(ACS-7):1-6.

(4.) Jayaraman G, Preiksaitis J, Larke B. Mandatory reporting of HIV infection and opt-out prenatal screening for HIV infection: Effect on testing rates. CMAJ 2003;168:679-82.

(5.) World Health Organization/Joint United Nations Programme for HIV/AIDS. HIV/AIDS programme. Strengthening health services to fight HIV/AIDS. Guidance on provider-initiated HIV testing and counselling in health facilities. Geneva, Switzerland: WHO, 2007.

(6.) Pope DS, DeLuca AN, Kali P, Hausler H, Sheard C, Hoosian E, et al. A cluster randomized trial of provider initiated (Opt-out) HIV counselling and testing of tuberculosis patients in South Africa. J Acquir Immune Defc Syndr 2008;48:190-95.

(7.) Sturtevant D, Preiksaitis J, Singh A, Houston S, Gill J, Predy G, et al. The feasibility of using an 'opt-out' approach to achieve universal HIV testing of tuberculosis patients in Alberta. Can J Public Health 2009;100(2):116-20.

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(9.) Public Health Agency of Canada. HIV/AIDS Epi Updates, November, 2007. Surveillance and Risk Assessment Division, Centre for Infectious Disease Prevention and Control, Public Health Agency of Canada, 2007.

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(11.) Alberta Health and Wellness. Provincial Program Development and Disease Control. 2008.

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(14.) Zencovich M, Kennedy K, MacPherson DW, Gushulak BD. Immigration medical screening and HIV infection in Canada. Int J STD and AIDS 2006;17:813 16.

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(17.) Health Canada. Research on HIV/AIDS in Aboriginal people: A background paper. Winnipeg, MB: Health Canada and University of Manitoba, 1998.

(18.) Cargill VA, Stone VE. HIV/AIDS: A minority health issue. Med Clin N Am 2005;89:895-912.

(19.) Diaz T, Chu SY, Buehler JW, Boyd D, Checko PJ, Conti L, et al. Socioeconomic differences among people with AIDS: Results from a multi-state surveillance project. Am JPrev Med 1994;10:217-22.

(20.) Wang F-L, Larke B, Gabos S, Hanrahan A, Schopflocher D. Potential factors that may affect acceptance of routine prenatal HIV testing. Can J Public Health 2005;96:60-64.

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Richard Long, MD, Jody Boffa, MIH

Author Affiliations

Tuberculosis Program Evaluation and Research Unit, Department of Medicine, University of Alberta, Edmonton, AB

Correspondence: Dr. Richard Long, Room 8325, Aberhart Hospital, 11402 University Avenue, Edmonton, AB T6G 2J3, Tel: 780-407-1427, Fax: 780-407-1429,

E-mail: richard.long@ualberta.ca

Conflict of Interest: None to declare.

Table 1. HIV Status of TB Patients in Alberta by Demographic
Group 2003-06 (previous report) *, 2007-08 (present report)

                                2003-2006

                   TB Cases    HIV Tested    HIV Positive
                                  n (%)          n (%)

Total                 496      406 (81.9)      22 (5.4)
Age (yrs)
  0-14                 19       10 (52.6)       0 (0.0)
  15-34               144      131 (91.0)       6 (4.6)
  35-64               198      168 (84.9)      16 (9.5)
  >64                 135       97 (71.9)       0 (0.0)
Male                  251      210 (83.7)      14 (6.7)
  Female              245      196 (80.0)       8 (9.5)
Population Group
([dagger])
  CBO                  61       52 (85.3)       0 (0.0)
  CBA                  66       58 (87.9)       5 (8.6)
  FBO                 293      231 (78.8)       6 (2.6)
  FBSSA                76       65 (85.5)      11 (16.9)

                                2007-2008

                   TB Cases    HIV Tested    HIV Positive
                                  n (%)          n (%)

Total                278       263 (94.6)      20 (7.6)
Age (yrs)
  0-14                17        14 (82.4)       0 (0.0)
  15-34               87        86 (98.9)       8 (9.2)
  35-64              107       107 (100.0)     12 (11.2)
  >64                 67        56 (83.6)       0 (0.0)
Male                 145       139 (95.9)      12 (8.3)
  Female             133       124 (93.2)       8 (6.0)
Population Group
([dagger])
  CBO                 32        29 (90.6)       0 (0.0)
  CBA                 31        28 (90.3)       5 (16.1)
  FBO                157       149 (94.9)       3 (1.9)
  FBSSA               58        57 (98.3)      12 (20.7)

* See reference #7

([dagger]) Abbreviations: CBO=Canadian-born 'other'; CBA=Canadian-born
Aboriginal; FBO=Foreign-born 'other'; FBSSA=Foreign-born sub-Saharan
African

Table 2. Demographic Features of HIV-negative and
HIV-positive TB Patients, Aged 15-64 Years, Alberta, 2003-08

                       HIV-negative        HIV-positive
                          n=450                n=42

Age (yrs)
  15-34                    203                  14
  35-64                    247                  28
Sex
  Male                     228                  26
  Female                   222                  16
Population Group *
  CBO                       48]                  0]
  FBO                      257]                  9]
  CBA                       58                  10
  FBSSA                     87                  23

                                  Univariate
                                  OR (95% CI)

Age (yrs)
  15-34                              1.00
  35-64                   1.64 (0.81, 3.47) (dagger])
Sex
  Male                               1.00
  Female                       0.63 (0.31, 1.26)
Population Group *
  CBO                                1.00
  FBO
  CBA                5.84 (2.02, 16.93) ([double dagger])
  FBSSA                 8.96 (3.80, 22.69) ([section])

                                  Multivariate
                                   OR (95% CI)

Age (yrs)
  15-34                               1.00
  35-64                  3.12 (1.36, 7.51) ([parallel])
Sex
  Male                                1.00
  Female                 0.75 (0.35, 1.56) ([paragraph])
Population Group *
  CBO                                 1.00
  FBO
  CBA                         4.96 (1.72, 14.52) **
  FBSSA               13.03 (5.17, 35.79) ([double dagger])

* Abbreviations: CBO=Canadian-born 'other'; FBO=Foreign-born 'other';
CBA=Canadian-born Aboriginal; FBSSA=Foreign-born sub-Saharan African

Note: The combination of CBO and FBO is the reference group for
comparison to CBA and FBSSA.  ([dagger]) p=0.15

([double dagger]) p<0.001

([section]) p<0.0001

([parallel]) p<0.005

([paragraph]) p<0.51

** p<0.003