Classification of Transmission Risk in the National HIV/AIDS Surveillance System

Transcription

1 Prctice Article Clssifiction of Trnsmission Risk in the Ntionl HIV/AIDS Surveillnce System Lis M. Lee, PhD Mtthew T. McKenn, MD Robert S. Jnssen, MD SYNOPSIS Risk behvior informtion is essentil for llocting resources nd developing effective HIV prevention strtegies. Over time, trnsmission risk informtion on HIV/AIDS cses hs been less likely to be reported to the ntionl surveillnce system. The Centers for Disese Control nd Prevention (CDC) invited pproximtely 30 experts in HIV/AIDS nd behviorl reserch from stte nd locl helth deprtments, cdemi, community-bsed orgniztions, nd the CDC to prticipte in consulttion in December 2001 to generte ides on how best to del with the lck of risk dt. The group ws chrged with providing recommendtions on methods for clssifying nd reporting risk informtion nd for identifying methods nd sources for improving scertinment of trnsmission risk behviors for individuls infected with HIV. This report describes the recommendtions nd the effects of implementing such recommended procedures on the ntionl HIV/AIDS surveillnce dtbse. Centers for Disese Control nd Prevention, Division of HIV/AIDS Prevention, Atlnt GA Address correspondence to: Lis M. Lee, PhD, 1600 Clifton Rd. NE, MS E-47, Atlnt GA 30333; tel ; e-mil 400

2 Clssifiction of Trnsmission Risk in the Ntionl HIV/AIDS Surveillnce System 401 HIV nd AIDS cse surveillnce in the United Sttes is defined s the ongoing nd systemtic collection, nlysis, interprettion, dissemintion, nd evlution of popultion-bsed informtion bout people infected with HIV or dignosed with AIDS. AIDS hs been reportble condition since the erly 1980s in ll 50 sttes, the District of Columbi, nd U.S. dependencies nd possessions in free ssocition with the U.S. These res report AIDS cses to the Centers for Disese Control nd Prevention (CDC) using uniform cse definition nd report form tht includes informtion on demogrphic chrcteristics, clinicl nd lbortory informtion, nd trnsmission risk behvior history. HIV cse reporting hs been prt of severl sttes comprehensive HIV/AIDS surveillnce systems since As of My 2003, 39 reporting res hve implemented nme-bsed HIV cse reporting s n extension of their AIDS cse reporting system. Sixteen res hve implemented HIV cse reporting using lternte or coded ptient identifiers, nd two reporting res do not require ny type of HIV cse reporting. The CDC begn integrting HIV cse reporting from sttes with nme-bsed systems into the AIDS reporting system in The primry gols of the ntionl HIV/AIDS surveillnce system re to monitor the epidemic by counting cses nd estimting incidence nd prevlence, nd to elucidte the epidemiology of HIV by nswering questions relted to person, plce, nd time. This informtion is then disseminted to people nd orgniztions with decision-mking nd resource lloction responsibilities. For exmple, in 2002, AIDS dt from the ntionl HIV/AIDS surveillnce system were used s prt of n lloction formul to fund over $1.9 billion in tretment nd cre progrms tht re dministered through the federl Helth Resources nd Services Administrtion (HRSA). Ultimtely, the purpose of these dt collection efforts is to guide public helth progrms nd prctice to prevent new HIV infections nd prevent morbidity nd mortlity in those lredy infected. HIV prevention services nd cre resources re often llocted bsed on reltive disese burden in trnsmission risk groups. Dt for trnsmission risk history re submitted to the HIV/AIDS reporting system on completed cse report forms from helth cre providers or trined helth deprtment personnel bstrcting in- nd outptient medicl records. At some sites, supplementl surveillnce ctivities re used to ugment stndrd medicl record reviews., It is rre tht risk behviors re collected s prt of routine disese surveillnce systems for other diseses, nd not ll helth cre providers scertin this informtion bout ptients or bout their ptients prtners. Ascertinment of ptients prtners risk behviors is especilly chllenging, but is necessry for clssifiction into the heterosexul contct (HC) risk ctegory, which is defined s heterosexul contct with person t risk for or infected with HIV. At the strt of the AIDS epidemic, when efforts were underwy to describe the epidemiology of n unknown pthogen, most medicl records contined informtion on trnsmission-relted behviors. With the current widespred vilbility of testing nd greter wreness of trnsmission risks, less trnsmission behvior informtion is vilble through medicl records. After consistent nd low percentge of AIDS cses with no risk reported (NRR) through the 1980s, there hs been n increse in the proportion of NRR cses, with high of 33% in Further, due to the greter number of cses to be investigted, there hve been fewer NRR cses clssified into known risk ctegory. Of AIDS NRR cses reported in 1992, 64% were eventully clssified, wheres of NRR cses reported in 2000, only 37% were clssified by the end of The effect of these two fctors hs been n increse in the ccumultion of cses without trnsmission risk behvior informtion in the ntionl system. In the fce of growing number of cses initilly reported without risk, the CDC developed sttisticl methods to mitigte bis introduced into the dt from missing risk behvior. Using historicl ptterns of clssifiction of NRR cses, the proportion of NRR cses clssified into known risk ctegory is clculted. These frctions re then used to distribute current NRR cses into risk ctegories, strtifying by sex, rce, nd region. While risk is not imputed for individul cses, the distribution of cses into risk ctegories is djusted. This method requires two mjor ssumptions. First, it ssumes tht the distribution of true risk mong NRR cses is homogeneous over time, which is unlikely to be true since chnges in high-risk behviors in some groups hs chnged the risk distribution over the pst decde. Second, the method ssumes tht NRR cses tht re clssified re representtive of ll NRR cses. This is less likely to be true now thn in the pst, s n incresed cselod hs prohibited systemtic follow-up of ll NRR cses, leving convenience smple of cses tht re chosen for investigtion or resolved through pssive scertinment from lter reports. Since the ssumptions of the risk redistribution hve become incresingly untenble, CDC invited pproximtely 30 experts in HIV/AIDS nd behviorl reserch from stte nd locl helth deprtments, cdemi, community-bsed orgniztions, nd the CDC to pr-

3 402 Prctice Article ticipte in consulttion in December 2001 to generte ides on how best to del with the lck of risk dt. The group ws chrged with providing recommendtions on methods for clssifying nd reporting risk informtion nd for identifying methods nd sources for improving scertinment of trnsmission risk behviors for individuls infected with HIV. The consulttion group recommended two chnges in how the CDC presents HIV/AIDS trnsmission risk dt. The first recommendtion ws to dopt probble heterosexul contct (PHC) ctegory to the list of current modes of exposure. PHC would be defined s hving one or more prtners of the opposite sex nd denil of ll other potentil modes of exposure (e.g., mle-to-mle sex [MSM], injection drug use [IDU], blood/blood products). Denil of other modes must be stted (i.e., cnnot be unknown ). The PHC ctegory would be in ddition to the current HC ctegory nd would differ from it by not requiring identifiction of the prtners risk for HIV trnsmission. Bsed on trnsmission probbilities nd difficulty ruling out other risk behviors mong men, including the stigm ssocited with homosexul ctivity, it ws thought tht PHC would be more relevnt for femle cses thn mle cses. The second recommended chnge in how the CDC presents risk dt ws to stop using the hierrchy of most probble mode of trnsmission (Tble 1) nd report mutully exclusive ctegories of ll risk behviors. The group recommended the mutully exclusive ctegories shown in Tble 2. Concurrently, in n ttempt to improve the chrcteriztion of HIV trnsmission in Michign, Schmidt et l. described the use of supplementl HIV/AIDS surveillnce projects to ugment dt reported to the HIV/AIDS surveillnce system. Using dditionl medicl record review dt from longitudinl medicl Tble 1. CDC hierrchy of the most probble mode of HIV trnsmission for dult/dolescent cses, 1993 to present Most probble mode of HIV trnsmission Mle-to-mle sexul contct (MSM) Injection drug use (IDU) MSM nd IDU Hemophili Heterosexul contct with person t risk for or infected with HIV Trnsfusion, trnsplnt Confirmed other Risk not specified record review project nd vlidtion study of HIV trnsmission risk fctors, the uthors exmined whether cses hd dditionl risk fctors tht were not cptured by using the CDC hierrchy of risk ctegories. Schmidt et l. proposed two chnges to the current presenttion of risk informtion. First, they recommended dding n IDU/HC ctegory to cpture the possible sexul trnsmission mong IDU cses. Second, they recommended tht the CDC dd presumed heterosexul contct ctegory for women tht includes cses tht fter thorough risk evlution, cnnot be clssified s IDU or HC in the risk hierrchy, but who hve been sexully ctive with one or more men. They suggested tht if ntionl dt support it, the ctegory should be pplied to men s well. We used vilble dt in the ntionl HIV/AIDS Reporting System (HARS) to ssess the usefulness of these recommended chnges for reporting of risk informtion for describing ntionl trnsmission risk behviors. METHODS We pplied the two dt presenttion recommendtions to the existing ntionl HIV/AIDS surveillnce dt. To clssify cses with insufficient risk informtion into the probble heterosexul ctegory, we used sex of the reported cse nd the vilble ncillry behvior risk informtion. Mle cses without n ssigned risk were clssified s PHC if their cse report form stted no for IDU, sex with mle, receipt of blood products nd tissue, worked in n helth cre or lbortory setting, nd HC with someone known to Tble 2. Mutully exclusive HIV trnsmission risk clssifiction ctegories recommended by expert consultnts, December 2001 Mutully exclusive HIV trnsmission risk clssifiction ctegories Mle-to-mle sexul contct (MSM) only MSM nd injection drug use (IDU) MSM nd heterosexul contct with person t risk for or infected with HIV (HC) MSM nd IDU nd HC IDU nd HC HC Probble heterosexul contct (PHC) Other (blood, tissue) PHC defined s hving one or more prtners of the opposite sex nd denil of ll other potentil modes of exposure (e.g., MSM, IDU, blood/blood products).

4 Clssifiction of Trnsmission Risk in the Ntionl HIV/AIDS Surveillnce System 403 be t risk for or infected with HIV, nd stted yes for sex with femle. Femle cses without n ssigned risk were clssified s PHC if their cse report form sid no for IDU, receipt of blood products nd tissue, worked in n helth cre or lbortory setting, nd HC with someone known to be t risk for or infected with HIV, nd stted yes for sex with mle. The distribution of risk ws compred when using risk s reported, risk s currently redistributed, nd risk s reported including the PHC ctegory. Becuse of concern tht the PHC ctegory would contin individuls (especilly men) who truly hve other, more probble risk behviors, we lso exmined the proportion of individuls with known MSM or IDU risk tht could be clssified s PHC if they hd denied MSM nd/or IDU. To present risk behvior dt without the hierrchy of the most probble trnsmission mode, we developed mutully exclusive ctegories using ll reported risk behviors. Upon closer exmintion of the consulttion recommendtion, we reconstructed the ctegories to include severl tht hd not been suggested. Our finl list contined the 17 ctegories shown in Tble 3. The distribution of risk behviors ws compred using risk s reported, risk s currently redistributed, nd risk in mutully exclusive ctegories. Anlyses were performed using ntionl HIV/AIDS surveillnce dt nd were bsed on cses dignosed in 1999, 2000, nd 2001 nd reported through September We used AIDS cse dt from ll reporting res nd HIV cse dt from 29 sttes tht hve hd nme-bsed HIV reporting since 1997 nd re considered systems from which new HIV dignoses for this period cn be exmined. (The sttes re: Albm, Arizon, Arknss, Colordo, Florid, Idho, Indin, Iow, Louisin, Michign, Minnesot, Missouri, Mississippi, Nevd, New Jersey, North Crolin, Nebrsk, New Mexico, North Dkot, Ohio, Oklhom, South Crolin, South Dkot, Tennessee, Uth, Virgini, West Virgini, Wisconsin, nd Wyoming.) RESULTS Presumed heterosexul contct Tble 4 compres the distribution of trnsmission risk t initil report, fter stndrd redistribution, nd using the PHC ctegory for AIDS cses. AIDS cse dt from ll reporting res resulted in 122,794 cses reported from 1999 through Among 91,448 men reported with AIDS, 18,994 (21%) were initilly reported without trnsmission risk. When PHC ws computed from extnt dt, 1,240 (1.4%) men were considered PHC, reducing the proportion with no trnsmission risk to Tble 3. Modified mutully exclusive HIV trnsmission risk ctegories used in nlysis of existing HIV/AIDS surveillnce dt Modified mutully exclusive HIV trnsmission risk ctegories Mle-to-mle sexul contct (MSM) only Injection drug use (IDU) only Heterosexul contct with person t risk for or infected with HIV (HC) only Presumed heterosexul contct (PHC) Other (blood, tissue, helthcre worker) only MSM nd IDU MSM nd HC MSM nd other IDU nd HC IDU nd other HC nd other MSM nd IDU nd HC MSM nd IDU nd other IDU nd HC nd other MSM nd IDU nd HC nd other No risk reported (t initil cse report) No identified risk (fter investigtion) PHC defined s hving one or more prtners of the opposite sex nd denil of ll other potentil modes of exposure (e.g., MSM, IDU, blood/blood products). 19.4%. When risk ws redistributed using the stndrd method, the proportion with no trnsmission risk ws reduced to 0.2%. The proportion in ll other ctegories incresed s those without risk were distributed ccording to historicl ptterns. Among 31,346 women reported with AIDS, 9,633 (30.7%) were initilly reported without trnsmission risk. When PHC ws computed from extnt dt, 642 (2.1%) women were considered PHC, reducing the proportion with no trnsmission risk to 28.7%. When risk ws redistributed using the stndrd method, the proportion with no trnsmission risk ws reduced to 0.43%. The proportion in ll other ctegories incresed s those without risk were distributed ccording to historicl ptterns. Tble 5 compres the distribution of trnsmission risk t initil report, fter stndrd redistribution, nd using the PHC ctegory for initil HIV dignoses. Initil HIV dignosis dt from the 29 reporting res resulted in 44,078 cses tht hd not progressed to AIDS reported from 1999 through Among 29,410 men reported with n initil HIV dignosis, 9,532 (32.4%) were initilly reported without trnsmission risk. Using the stndrd method, when risk ws redis-

5 404 Prctice Article Tble 4. Percentge distribution of HIV trnsmission risk s reported, fter stndrd redistribution, with the ddition of presumed heterosexul contct (PHC), nd using mutully exclusive risk ctegories, AIDS dignoses , U.S., n=122,794 Risk redistributed, Mutully using current exclusive Risk s reported, sttisticl PHC, using ctegories, using using current redistribution recommended recommended hierrchy method definition ctegories Mle Femle Mle Femle Mle Femle Mle Femle MSM IDU MSM/IDU HC Other Undetermined PHC MSM/HC 2.9 MSM/Other 0.2 IDU/HC IDU/Other HC/Other MSM/IDU/HC 1.1 MSM/IDU/Other 0.02 MSM/HC/Other 0.03 IDU/HC/Other MSM/IDU/HC/Other 0.02 Adjusted for reporting dely MSM=mle-to-mle sex IDU=injection drug use HC=heterosexul contct Other includes ll confirmed other modes of trnsmission (e.g., blood/blood products, trnsplnt, helth cre worker exposure). NOTES: My not totl 100% due to rounding. A dsh ( ) indictes not pplicble. A blnk indictes not considered. tributed for HIV cses, the proportion with no trnsmission risk ws set to 0%. The proportion in ll other ctegories incresed s those without risk were distributed ccording to historicl ptterns. When PHC ws computed from extnt dt, 545 (1.9%) men were considered PHC, reducing the proportion without trnsmission risk to 30.6%. Among 14,668 women reported with n initil HIV dignosis, 6,346 (43.3%) were initilly reported without trnsmission risk. Using the stndrd method, when risk ws redistributed for HIV cses, the proportion with no trnsmission risk ws set to 0%. The proportion in ll other ctegories incresed s those without risk were distributed ccording to historicl ptterns. When PHC ws computed from extnt dt, 450 (3.1%) women were considered PHC, reducing the proportion without trnsmission risk to 40.2%. To exmine the effect of potentil misclssifiction of PHC, we exmined the proportion of individuls with known MSM nd IDU risk tht would be clssified s PHC if they hd denied MSM or IDU. Among 40,243 MSM AIDS cses dignosed from 1999 through 2001, 2,319 (5.7%) would be misclssified s PHC if MSM were denied. Among 17,380 mle nd 7,610 femle IDU cses, 2,228 (12.8%) nd 766 (10.1%) would be misclssified s PHC if IDU hd been denied. Percentges were similr mong HIV dignoses tht hd not progressed to AIDS (dt not shown).

6 Clssifiction of Trnsmission Risk in the Ntionl HIV/AIDS Surveillnce System 405 Tble 5. Percentge distribution of HIV trnsmission risk s reported, fter stndrd redistribution, with the ddition of presumed heterosexul contct (PHC), nd using mutully exclusive risk ctegories, HIV dignoses not progressing to AIDS , 29 HIV-reporting sttes, U.S., n=44,078 Risk redistributed, Mutully using current exclusive Risk s reported, sttisticl PHC, using ctegories, using using current redistribution recommended recommended hierrchy method definition ctegories Mle Femle Mle Femle Mle Femle Mle Femle MSM IDU MSM/IDU HC Other Undetermined b 0.0 b PHC MSM/HC 4.1 MSM/Other 0.1 IDU/HC IDU/Other HC/Other MSM/IDU/HC 0.9 MSM/IDU/Other 0.02 MSM/HC/Other 0.03 IDU/HC/Other MSM/IDU/HC/Other 0.01 Adjusted for reporting dely b Undetermined set to 0.0 in modeling risk redistribution MSM=mle-to-mle sex IDU=injection drug use HC=heterosexul contct Other includes ll confirmed other modes of trnsmission (e.g., blood/blood products, trnsplnt, helth cre worker exposure). NOTE: My not totl 100% due to rounding. A dsh ( ) indictes not pplicble. A blnk indictes not considered. Mutully exclusive risk ctegories Removl of the hierrchicl structure of trnsmission risk ctegories results in the ddition of 11 ctegories (Tbles 4 nd 5). All originl hierrchy ctegories represent smller proportion of cses. Ech dditionl ctegory constitutes less thn 9% of cses, rnging from 8.5% for femle IDU/HC to 0.01% for mle MSM/IDU/HC/other. DISCUSSION Using currently vilble informtion on risk behviors in the ntionl HIV/AIDS surveillnce dtbse, we were ble to clssify only 1.4% to 3.1% of cses initilly clssified s no risk reported into presumed heterosexul ctegory (defined s sexul contct with opposite-sex prtner nd denil of ll other risk fctors). Men were less likely thn women to be clssified s PHC nd hd greter chnce of being misclssified s presumed heterosexul compred with women. Our inbility to clssify more cses into PHC ws relted to the lrge proportion of cses with missing or unknown risk behvior dt. Among mle AIDS cses, for exmple, 40% hd missing or unknown informtion on sex with femle, 35% hd missing or unknown informtion on sex with mle, nd 48% hd missing informtion on IDU. Among femle AIDS cses, 21% hd missing or unknown sex with mle nd 52%

7 406 Prctice Article hd missing informtion on IDU. The proportion of cses with missing or unknown dt in behvior risk fields vried by sex nd reporting site (dt not shown). Without cknowledgement of sexul contct with n opposite-sex prtner nd denil of other risk behviors, PHC could not be ssigned. Assignment of NRR to PHC might be more successful in sttes or locl res where supplementl surveillnce projects re conducted, llowing collection of dditionl informtion from ptient interview 3 nd review of medicl records t regulr intervls. 2 Using supplementl surveillnce dt in Michign, Schmidt et l. 5 were ble to document dditionl risk behviors on reported HIV cses. However, during our nlysis period, only eight of the 29 HIV-reporting sttes used in this nlysis were implementing supplementl surveillnce ctivities similr to those vilble in the nlysis from Michign. 5 PHC my be less pplicble to men, s it is often difficult to rule out MSM, resulting in n undercount of cses ttributed to MSM. A multi-site vlidtion study of risk behviors in the AIDS reporting system in the mid-1990s indicted tht heterosexul risk ws overestimted for women by up to 29% nd for men by up to 70%. 6 In ddition, most studies suggest tht femle to mle trnsmission of HIV is less efficient thn mle to femle trnsmission. 7 Removing the risk behvior hierrchy, we dded 11 ctegories. Ech dditionl ctegory constituted smll proportion of cses, nd the proportion of cses without risk remined high. Too mny ctegories cn be unwieldy for interprettion, especilly if the proportions re low in most groups. Presenting these exhustive, mutully exclusive risk ctegories is only s effective s dt collection is complete. As is the cse with ssignment of PHC, incomplete risk behvior informtion in our dt limited our bility to ssign cses into finer ctegories. Completeness of dt collection for risk behviors would need to improve for this presenttion to be beneficil. However, with improved dt collection, this method of presenttion would enble us to void ssumptions bout which trnsmission mode is more likely if more thn one is present, to present dt s they re collected, nd to identify growing ctegories tht might be overshdowed by combining into broder group. Our inbility to reduce substntilly the proportion of NRR cses in the ntionl dtbse simply by creting dditionl ctegories or ssigning cses to PHC bsed on currently vilble dt suggests mesurement or informtion scertinment issue. The CDC is piloting severl efforts to improve scertinment of trnsmission risk. Twelve res hve been funded to evlute nd refine stndrd protocol tht exmines existing records to ssess the most efficient nd costeffective sources of risk informtion. In ddition, we pln to identify nd evlute brriers fced by helth cre providers in collecting nd documenting HIV trnsmission risk. Bsed on identified brriers, we pln to develop interventions to improve providers scertinment nd documenttion of this criticl informtion. We re collecting supplementl high risk behvior informtion, including exchnging sex for drugs or money, use of illicit non-injection drugs, nd recent history of other sexully trnsmitted infections on smple of cses with heterosexul contct tht does not fit the current CDC hierrchy definition. We will exmine whether these dt fcilitte the cretion of stndrd definition for high-risk heterosexul behvior. Finlly, six high-morbidity res hve been funded to pilot smpling methods llowing us to mke inference bout trnsmission risk from representtive smple to the popultion of ll persons with dignosed HIV disese in these six res. A scientific pproch using stndrd definition of high-risk heterosexul behvior hs been recommended over the presumption tht cses hving heterosexul prtners nd no other reported risk fctor be designted s presumed heterosexul contct. 8 It is cler tht effective surveillnce of HIV risk behviors mong individuls with newly dignosed HIV will require vriety of dt collection strtegies nd sttisticl pproches. The CDC will use the dt from these pilot studies to improve the completeness nd ccurcy of dt on trnsmission risk behviors nd to guide the development of ny chnges to the HIV trnsmission mode hierrchy. The uthors thnk Mon Sriy, MD, MPH, nd John E. Gerstle III, MS, for their ssistnce with dt preprtion, nd Dnni Dniels, MS, for criticl review of n erlier drft of the mnuscript. REFERENCES 1. Nkshim AK, Fleming PL. HIV/AIDS surveillnce in the United Sttes, J Acquired Immune Defic Syndr 2003;32 Suppl 1: Frizo K, Buehler J, Chmberlnd M, Whyte B, Froelicher E, Hopkins S, et l. Spectrum of disese in persons with humn immunodeficiency virus infection in the United Sttes. JAMA 1992;267: Buehler JW, Diz T, Hersh BS, Chu SY. The supplement to HIV-AIDS surveillnce project: n pproch for monitoring HIV risk behviors. Public Helth Rep 1996; 111Suppl 1: Green TA. Using surveillnce dt to monitor trends in the AIDS epidemic. Stt Med 1998;17: Schmidt MA, Mokotoff ED. HIV/AIDS surveillnce nd

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