Transcript Document 7212006

Health worker absence, HIV testing
and behavioral change
Markus Goldstein (World Bank)
Joshua Graff Zivin (UCSD)
James Habyarimana (Georgetown)
Kiki Pop-Eleches (Columbia)
Harsha Thirumurthy (UNC-Chapel Hill)
Information and behavior
• Information assumed to shape choices and behavior
• This has implications for effects of HIV testing
 Provides information about future health and longevity
• Setting for this study
 Antenatal clinic in Kenya where testing is offered to pregnant
women for prevention of MTCT
• Aim: study take-up of HIV testing and impact of
learning HIV status on behavioral outcomes
Two important aspects of HIV testing
• Take-up of HIV testing
 Supply and demand side factors influence this, but role of
each not well understood
• Should testing be an important component of policy
response to HIV?
 Discussion has largely focused on its impact on sexual
behavior (Coates et al. 2000; Thornton 2008)
 Impacts on other outcomes largely neglected
• Take-up of other valuable health services
• forward-looking behavior
Obstacles to scale-up of HIV testing
• Supply and demand side factors
 Demand side factors (see Thornton 2008 & others)
• This paper focuses on supply side
 Structural constraints (health worker absence)
• Health worker absence in developing world
 35% absence rate among public health providers
(Chaudhury et al. 2005)
 Limited evidence re: impact on health outcomes
• Also a valid instrument for testing decision
Effects of HIV testing (1): health
outcomes
• Main reason for testing pregnant women: provide
PMTCT medication & advice
 In 2005, 11% of HIV+ women in Africa got PMTCT
• Inexpensive & effective meds available for PMTCT
 Nevirapine ($0.50 per dose)
 In this setting, ARV therapy also given for PMTCT
• Other possible benefits of PMTCT counseling
 Healthier mothers and children through safer delivery and
increased take-up of neonatal care
Effects of HIV testing (2): socioeconomic behavior
• Information about future health & expected longevity
should affect number of inter-temporal investment
decisions at household level
 Fertility – important assumption in macro models of impact
of AIDS epidemic (Young 2005)
 Human capital formation
 Asset accumulation
TESTING AND COUNSELLING: HEALTH OUTCOMES
BREAST
FEED
Individual
ANC
HEALTH
OUTCOMES
TEST
BIRTH
LOCATION
Structural
Inputs
PMTCT
TESTING AND COUNSELLING: ECONOMIC OUTCOMES
FERTILITY
Individual
ANC
ECONOMIC
OUTCOMES
TEST
SCHOOLING
Structural
Inputs
INVESTMENT
Summary of results
• Absence rate of 10% of PMTCT nurse
 Large effect on uptake of testing and counseling
• Large effect on delivery of PMTCT medications
 Safer delivery
 Lower likelihood of breastfeeding
• Change in investment behavior among negatives
 Asset accumulation
 Schooling
• No effects on fertility preferences
Outline
• Panel survey of pregnant women in Kenya
• HIV testing decisions and nurse absence
Survey in Nyanza Province
Kenya adult prevalence 6.7% (1.2
million)
 Nyanza Province adult
prevalence of 20%
Rural health center provides
ANC care, and has HIV clinic
that provides ARVs (managed
by AMPATH program)
Survey conducted in two waves
Panel survey of pregnant women
• Wave 1: In-clinic interview before HIV test (July ‘05 – Feb ‘06)
 Only first time visitors for current pregnancy interviewed
 Short questionnaire, included subjective beliefs about HIV status
 650 women from catchment area enrolled
• HIV testing offered after wave 1 interview
• Wave 2: Household interview (May ‘06 – Feb ‘07)
 comprehensive socio-economic data collected at home:
• demographics, education, health, employment, sexual behavior, assets, etc
• Interviewed ANC client and spouse
• Completed panel on 591 women (9% attrition)
• Loss to follow up generally due to relocation out of province
Additional data obtained from clinic
• PMTCT logbook
 HIV status: continuously updated because pregnant women
could have tested on subsequent antenatal visits
 Nurse presence/absence: based on # of women tested
• AMPATH records
 Fraction of HIV+ women who enrolled (imperfect
matching)
PMTCT in western Kenya
• Pregnant women typically get tested at first ANC visit
 3 visits recommended
• Most common med for HIV+ women: Nevirapine
 Given to the mother with onset of labor and drops given to
the baby within 72 hours of birth
 Reduces the risk of transmission by about 50%
• In our study setting, ART also given for PMTCT
• Breastfeeding generally not recommended
HIV testing in sample of 591 women
HIV status of women
22.8%
15.2%
61.9%
Negative
Not tested
Source: Chulaimbo ANC Intake, 2006
Positive
Health worker absence & HIV testing
• About 77% of women in panel data tested for HIV
 25% of those who tested were HIV+
• Controlling for selection into testing
 10% absence rate for PMTCT nurse (relatively small)
• Useful as an instrumental variable to deal with selection
 Effect of absence on testing is first stage
 Also control for day of the week and prior beliefs
Table 2a: Nurse absence and testing
Table 2b
Nurse present at time of woman's first visit
Age in years
Completed primary school
Married
# of church attendances (past 4 wks)
Number of sexual partners (past 6 mths)
Boils drinking water
HIV subjective beliefs
Moderate chance
Small chance
No chance at all
Livestock ownership
House has non-grass roof
Household resides in clinic catchment
(1)
0.001
(0.002)
-0.020
(0.026)
0.021
(0.039)
0.011
(0.004)*
0.007
(0.035)
0.035
(0.026)
(2)
0.001
(0.002)
-0.017
(0.026)
0.027
(0.038)
0.012
(0.004)**
0.010
(0.034)
0.038
(0.025)
0.012
(0.039)
-0.029
(0.037)
-0.071
(0.049)
0.003
(0.002)
-0.033
(0.028)
-0.001
(0.028)
0.010
(0.040)
-0.032
(0.038)
-0.078
(0.049)
0.003
(0.002)*
-0.032
(0.028)
-0.001
(0.028)
-0.013
(0.029)
-0.028
(0.030)
-0.085
(0.033)**
-0.193
(0.046)**
0.909
(0.080)**
574
0.08
Day of week = Tuesday
Day of week = Wednesday
Day of week = Thursday
Day of week = Friday
Constant
Observations
R-squared
0.865
(0.081)**
577
0.03
HIV testing and behavior change
• Instrument for testing offers opportunity to examine
whether behavior changes after learning HIV status
 We estimate separate effects for HIV- and HIV+ women
• Comparison group?
 We compare to women who do not get tested but have
similar pre-test beliefs about own status
IV strategy for estimating impact of
testing (by test result)
• Ideally:
 Do not know status for non-testers
• Therefore, we assume that
 Control for pre-test subjective beliefs
 Our assumption (non-testers’ behavior shaped by beliefs)
Subjective beliefs about HIV status
• First, are pre-test subjective beliefs good proxy for HIV
status?
 i.e. do pre-test beliefs predict actual test result?
• Second, do beliefs change after learning HIV status?
 Perhaps a prerequisite for behavioral change to occur
 We examine beliefs about own status and partner’s status
Variation in pre-test subjective beliefs
Distribution of priors
17.7%
12.1%
18.5%
51.8%
Great
Small
Source: Chulaimbo ANC Intake, 2006
Moderate
None at all
Pre-test beliefs do have predictive power
Distribution of priors
Negative
Positive
8.9%
17.8% 10.7%
21.1%
18.9%
44.4%
25.6%
52.6%
Not tested
23.1%
Total
9.7%
17.7% 12.1%
12.7%
18.5%
51.8%
54.5%
Great
Small
Source: Chulaimbo ANC Intake, 2006
Moderate
None at all
Pre-test beliefs & actual test result
Chance of having HIV- great
Chance of having HIV- moderate
Chance of having HIV- small
Day of week controls?
Other controls
Mean of dep. variable
Sample Size
Tested
positive
(1)
Tested
positive
(2)
Tested
positive
(3)
0.272
(0.097)**
0.171
(0.081)*
0.077
(0.059)
0.267
(0.098)**
0.168
(0.082)*
0.079
(0.059)
0.226
(0.098)*
0.126
(0.080)
0.055
(0.059)
N
N
0.197
453
Y
N
0.197
452
Y
Y
0.197
452
Testing and changes in subjective beliefs
HIV testing and behavior change
• Evidence of changes in subjective beliefs about one’s
status provide motivation for other behavioral
responses
• We first estimate average effect across all women who
learn they are HIV+ and HIV- (not interacted with
pre-test beliefs)
Why pre-test beliefs may matter
(Boozer & Philipson 2000)
Costs and Benefits of
testing
Benefit of testing
Cost of testing
Low-risk
High-risk
Prior belief (subj.
belief)
Literature has focused largely on the
effect of HIV testing on sexual behavior
• Policy rationale
 Those who test HIV- may have incentives to avoid infection
 Those who test HIV+ can be encouraged to adopt safe sex
practices
• Effects are theoretically ambiguous
 In both cases, the opposite response possible
• Existing studies of testing and sexual behavior
 Coates el al. 2000: VCT, Kenya and Tanzania
 Thornton 2005: community-based VCT, Malawi
Impacts on other outcomes also
important for evaluation of HIV testing
• PMTCT take-up, health outcomes
• Socio-economic behavior, particularly forward-looking
decisions
Effects on PMTCT and health
outcomes
Socio-economic behavior
Heterogeneous response by level of
surprise and updating
• As in Boozer and Philipson (JHR 2000)
• Do women who learn more from the HIV test have
larger changes in behavior?
 Not much evidence that this matters
 Actual test result is more salient than how surprised one is by
the test result
Summary of results
• Absence rates are moderate but have large
effects on PMTCT outcomes
• Pre-test beliefs do predict HIV status, and
these beliefs evolve over time
• Increases in investment behavior for
women who test HIV-negative
• No effect on fertility