Evaluating linkage to care for hypertension after community-based screening in rural Uganda

Authors

  • Prashant Kotwani,

    1. Division of HIV/AIDS, San Francisco General Hospital, University of California San Francisco, San Francisco, CA, USA
    2. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Laura Balzer,

    1. School of Public Health, University of California, Berkeley, CA, USA
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  • Dalsone Kwarisiima,

    1. Makerere University Joint AIDS Program, Kampala, Mbarara, Uganda
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  • Tamara D. Clark,

    1. Division of HIV/AIDS, San Francisco General Hospital, University of California San Francisco, San Francisco, CA, USA
    2. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Jane Kabami,

    1. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Dathan Byonanebye,

    1. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Bob Bainomujuni,

    1. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Douglas Black,

    1. Division of HIV/AIDS, San Francisco General Hospital, University of California San Francisco, San Francisco, CA, USA
    2. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Gabriel Chamie,

    1. Division of HIV/AIDS, San Francisco General Hospital, University of California San Francisco, San Francisco, CA, USA
    2. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Vivek Jain,

    1. Division of HIV/AIDS, San Francisco General Hospital, University of California San Francisco, San Francisco, CA, USA
    2. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Harsha Thirumurthy,

    1. Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
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  • Moses R. Kamya,

    1. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
    2. Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
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  • Elvin H. Geng,

    1. Division of HIV/AIDS, San Francisco General Hospital, University of California San Francisco, San Francisco, CA, USA
    2. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Maya L. Petersen,

    1. School of Public Health, University of California, Berkeley, CA, USA
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  • Diane V. Havlir,

    1. Division of HIV/AIDS, San Francisco General Hospital, University of California San Francisco, San Francisco, CA, USA
    2. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
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  • Edwin D. Charlebois,

    Corresponding author
    1. Makerere University-University of California San Francisco Research Collaboration, Mbarara, Kampala, Uganda
    2. Center for AIDS Prevention Studies, University of California San Francisco, San Francisco, CA, USA
    • Corresponding Author Edwin D. Charlebois, Center for AIDS Prevention Studies, Department of Medicine, University of California San Francisco, 50 Beale Street, Suite #1300, San Francisco, CA 94105, USA. Tel.: +1 415 597 9301; Fax: +1 415 597 9213; E-mail: edwin.charlebois@ucsf.edu

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  • The SEARCH Collaboration


Abstract

Objectives

To determine the frequency and predictors of hypertension linkage to care after implementation of a linkage intervention in rural Uganda.

Methods

During a multidisease screening campaign for HIV, diabetes and hypertension in rural Uganda, hypertensive adults received education, appointment to a local health facility and travel voucher. We measured frequency and predictors of linkage to care, defined as visiting any health facility for hypertension management within 6 months. Predictors of linkage to care were calculated using collaborative-targeted maximum likelihood estimation (C-TMLE). Participants not linking were interviewed using a standardised instrument to determine barriers to care.

Results

Over 5 days, 2252 adults were screened for hypertension and 214 hypertensive adults received a linkage intervention for further management. Of these, 178 (83%) linked to care within 6 months (median = 22 days). Independent predictors of successful linkage included older age, female gender, higher education, manual employment, tobacco use, alcohol consumption, hypertension family history and referral to local vs. regional health centre. Barriers for patients who did not see care included expensive transport (59%) and feeling well (59%).

Conclusions

A community health campaign that offered hypertension screening, education, referral appointment and travel voucher achieved excellent linkage to care (83%). Young adults, men and persons with low levels of formal education were among those least likely to seek care.

Abstract

Objectifs

Déterminer la fréquence et les facteurs prédictifs de la liaison de l'hypertension aux soins après l'implémentation d'une intervention de liaison en zone rurale, en Ouganda.

Méthodes

Au cours d'une campagne de dépistage de plusieurs maladies pour le VIH, le diabète et l'hypertension en zone rurale, en Ouganda, les adultes hypertendus ont reçu une éducation, un assignement à un centre de santé local et des bons de voyage. Nous avons mesuré la fréquence et les facteurs prédictifs de la liaison aux soins, définie comme la visite d'un établissement de soins pour la prise en charge de l'hypertension dans les 6 mois. Les facteurs prédictifs de la liaison aux soins ont été déterminés en utilisant une estimation du maximum de vraisemblance de collaboration ciblée (C-TMLE). Les participants sans liaison ont été interrogés à l'aide d'un outil standardisé afin de déterminer les obstacles aux soins.

Résultats

Sur 5 jours, 2252 adultes ont été dépistés pour l'hypertension et 214 adultes hypertendus ont reçu une intervention de liaison pour une prise en charge supplémentaire. Parmi ceux-ci, 178 (83%) étaient reliés aux soins endéans les 6 mois (médiane = 22 jours). Les facteurs prédictifs indépendants de la liaison réussie comprenaient: l’âge avancé, le sexe féminin, un niveau d’éducation plus élevé, l'emploi manuel, l'usage du tabac, la consommation d'alcool, des antécédents familiaux d'hypertension et l'orientation vers un centre de santé local plutôt que régional. Les obstacles pour les patients qui n'ont pas recouru à des soins comprennent: le transport cher (59%) et le fait de se sentir bien (59%).

Conclusions

Une campagne de santé communautaire qui offre le dépistage de l'hypertension, l’éducation, des rendez-vous d'orientation et des bons de voyage a obtenu une excellente liaison aux soins (83%). Les jeunes adultes, les hommes et les personnes ayant un faible niveau d’éducation officielle étaient parmi les moins susceptibles de recourir à des soins.

Abstract

Objetivos

Determinar la frecuencia y los vaticinadores de la remisión a cuidados por hipertensión después de la implementación de una intervención de remisión en Uganda rural.

Métodos

Durante una campaña de despistaje múltiple para VIH, diabetes e hipertensión en zonas rurales de Uganda, los adultos con hipertensión recibieron formación, una cita para un centro sanitario local y un bono de transporte. Hemos medido la frecuencia y los vaticinadores de remisión a cuidados, definido como haber visitado cualquier centro sanitario para el manejo de la hipertensión en los últimos 6 meses. Los vaticinadores de la remisión a cuidados se determinaron utilizando el C-TMLE (por sus siglas en inglés collaborative targeted maximum likelihood estimation). A aquellos participantes que no cumplieron con las citas a las que se les había remitido, se les entrevistó utilizando un instrumento estandarizado para determinar las barreras a la atención sanitaria.

Resultados

Durante 5 días se realizó la prueba para la hipertensión a 2252 adultos y 214 adultos con hipertensión fueron remitidos para recibir más atención sanitaria. De ellos, 178 (83%) recibieron atención, fueron remitidos y cumplieron con las citas médicas dentro de los siguientes 6 meses (mediana = 22 días). Los vaticinadores independientes de una remisión exitosa incluían una mayor edad, ser del género femenino, tener un mayor nivel de educación, empleo manual, uso de tabaco, consumo de alcohol, historia de hipertensión familiar y remisión a un centro local versus a un centro sanitario regional. Las barreras para los pacientes que no recibieron atención sanitaria posterior incluían un transporte costoso (59%) y el sentirse bien (59%).

Conclusiones

Una campaña comunitaria que ofrecía despistaje para la hipertensión, educación, remisión y cita médica concertada en un centro y bono de transporte, consiguió un alto nivel de éxito en la remisión (83%). Los adultos jóvenes, hombres y personas con niveles bajos de educación formal estaban entre aquellos con menor probabilidad de buscar cuidados.

Introduction

Community- and home-based HIV screening programmes are cost-effective and successful methods to reach large numbers of previously untested individuals (Morin et al. 2006; Menzies et al. 2009; Negin et al. 2009; Grabbe et al. 2010; Lugada et al. 2010; Tumwesigye et al. 2010; Granich et al. 2012). Given the high burden of other chronic diseases in sub-Saharan Africa, these innovative screening programmes also are a unique opportunity to diagnose and treat individuals with diseases other than HIV, such as hypertension. This approach builds efficiency by leveraging resources invested in HIV testing campaigns as a platform to provide diagnostic services for non-communicable diseases (NCD) (Chamie et al. 2012).

Hypertension is a high-burden NCD that is particularly well suited to community-based screening approaches given the ease and speed of sphygmomanometry. However, diagnosis is only the first step in the ‘cascade of care’ that begins with diagnosis and proceeds to linkage, initiating therapy, retention and eventual control of disease (summarised in Figure 1).

Figure 1.

Hypertension care cascade. A concept map outlining each step involved in the successful treatment for hypertension. This process begins with community or clinic-based hypertension screening initiatives. Once hypertension is diagnosed, the next key steps – linkage, retention and re-engagement – ensure continued engagement in care. These steps are crucial to retain patients in care and achieve successful blood pressure control. HTN, hypertension. Adapted from (Mugavero et al. 2011).

Data on retention of hypertensive patients through all steps in the care cascade in resource-limited settings are lacking. A previous study found low utilisation of healthcare services after hypertension screening in Tanzania, but did not include a linkage intervention (Bovet et al. 2008). Only 32% follow-up was reported after hypertension and diabetes screening in Cameroon despite the use of a linkage intervention (Gessler et al. 2012). Similarly, a recent study in Kenya found poor linkage to care after community-based screening (31%) but had a very small sample size (35 persons) (Pastakia et al. 2013). To our knowledge, there has not been a robust assessment of hypertension linkage to care following community-based screening in sub-Saharan Africa.

The Sustainable East Africa Research in Community Health (SEARCH) collaboration has pioneered multidisease screening that integrates HIV and NCD services through community health campaigns (Chamie et al. 2012). In a pilot campaign conducted in May 2011 in rural southwestern Uganda, we found a significant burden of untreated hypertension but inadequate follow-up after screening (Chamie et al. 2012). In an effort to understand the second step in the cascade of hypertension care, in this subsequent study, we have tested a linkage strategy including education, referral appointment to a health facility and transport voucher. Using a community-based screening campaign, the primary objective of this study was to determine the frequency and predictors of hypertension linkage to care following implementation of a linkage intervention in rural Uganda. A secondary objective was to describe barriers to hypertension care in rural Uganda.

Methods

Study design and setting

This was a prospective substudy on hypertension linkage to care nested within a multidisease community health campaign (CHC). The study was conducted in May 2012 in Kakyerere parish, a community of approximately 6300 persons in Mbarara district in southwestern Uganda.

Community health campaign

This public health initiative brings rapid diagnostic services for multiple diseases to rural populations. The CHC is a high-throughput event staffed by local health personnel, offering services to all community members (approximately 1000 persons/day) at accessible community sites such as schools or churches. The campaign occurs over 5 days and each adult participant receives point-of-care screening for HIV, hypertension and diabetes. Children are offered HIV testing, rapid diagnosis and treatment for malaria as well as deworming. The average transit time for the campaign is approximately 90 min. Our group previously described the implementation of a CHC in Mbarara, Uganda in 2011 (Chamie et al. 2012).

Hypertension screening and study population

All community members were invited to participate in the CHC. Each adult responded to an epidemiologic survey ascertaining basic demographics, occupational and medical history, as well as substance use. Next, trained staff conducted blood pressure (BP) measurements using an electronic, automated sphygmomanometer (Honsun LD7A). Subjects were seated in a chair and rested for approximately one minute before BP was measured. High BP was defined as systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg. Persons with high BP underwent two confirmatory measurements one minute apart. The lowest of three measurements was then used to establish a diagnosis of hypertension to minimise over-diagnosis (false positives) using a single BP measure. In addition, height (to the nearest 0.1 cm) and weight (to the nearest kilogram) were measured to calculate body mass index (BMI) for each participant. Point-of-care random plasma glucose and HIV rapid testing were also performed.

All adults at the CHC who were hypertensive on screening and self-reported not currently receiving antihypertensive therapy were invited to participate in the linkage to care study.

Hypertension linkage intervention

The linkage to care intervention included education, referral appointment to a health facility and transport voucher. Each participant received an individualised counselling session with an experienced nurse, which included education about the chronic nature of hypertension, possible complications of untreated disease, need for lifestyle modifications and potential necessity for lifelong medications. Each session lasted 5–10 min and was performed by the same nurse for all subjects. Participants were then given a referral appointment to the nearest local health centre (Bwizibwera Health Center IV) or the regional hospital (Mbarara Regional Referral Hospital) if hypertensive urgency was diagnosed (systolic BP ≥180 mmHg or diastolic BP ≥110 mmHg). Appointments were scheduled 3–30 days after screening.

The local health centre was approximately 5 km away from Kakyerere parish, whereas the regional hospital was about 30 km away. The cost of a one-way journey to the local health centre is approximately 2 United States Dollars (USD), while the cost for a one-way journey to the regional hospital is approximately 4 USD. Participants were given a travel voucher that could be reimbursed for a nominal amount upon successful linkage at the local health centre or regional hospital. This amount was similar to the cost of a one-way journey: 5000 Ugandan Shillings (USh; approximately 2 USD) for the local health centre and 10000 USh (approximately 4 USD) for the regional hospital.

At either health facility, participants were treated per the Ugandan Ministry of Health guidelines. Government health facilities in Uganda are required to provide free services to all patients, including antihypertensive medication. Those with refractory hypertension or complications are usually referred to the regional hospital. However, these health facilities occasionally run out of medications, which forces patients to purchase medications from private retail pharmacies. Previously, the monthly cost of purchasing antihypertensive medicines has been estimated to be 1.1 Euros (1.4 USD) in a similar region (Labhardt et al. 2011).

Tracking

Linkage visits were captured using handwritten logbooks at the local health centre and the referral hospital. Travel vouchers with unique study identifiers served to accurately identify participants who successfully linked to care. Participants who did not visit either health facility within 6 months were tracked to determine care status and assess barriers to care. We adapted tracking methods previously implemented in rural Uganda among patients with HIV (Geng et al. 2010).

A trained tracker conducted a standardised interview to assess care status and barriers to care. The tracker was given a list of subjects including their pertinent identifiers (name, sex, age and occupation) and residence information (GPS coordinates and village). GPS coordinates were collected during a community-wide household census prior to the CHC. For participants who provided a cellphone number, the tracker first attempted to conduct a phone interview. If unable to conduct a phone interview or no phone number was available, the tracker visited participants at their home to determine care status. If the tracker failed to locate the participant on the first visit, at least two more attempts were made. Failing this, the tracker recorded care status information from close informants (family members, neighbours or friends), if known.

Data analysis

Survey data at the CHC were collected via pre-programmed tablets. Tracking interview data were double entered into microsoft access. stata v.12 (Stata Corporation) and r v.2.15.3 (R Core Team, 2013) were used for analyses.

Successful linkage to care was defined as visiting any clinic for hypertension care within 6 months. Factors analysed as predictors of linkage to care were age, gender, level of education, occupation, smoking status, alcohol consumption, family history of hypertension, time to appointment, site of appointment (local health centre or regional hospital) and severity of hypertension (Stage 1 or Stage 2). Stage 1 hypertension was defined as systolic BP 140–159 and/or diastolic BP 90–99 mmHg; and Stage 2 hypertension was defined as systolic BP ≥160 or diastolic BP ≥100 mmHg (Chobanian et al. 2003).

For each predictor variable, collaborative-targeted maximum likelihood estimation (C-TMLE) was used to estimate the marginal difference in the probability of linking, after adjusting for the other predictor variables (Gruber & van der Laan 2011). C-TMLE was implemented instead of parametric logistic regression for several reasons. First, we wished to obtain point estimates on the additive scale, instead of estimates on the relative scale, such as odds ratios. Secondly, C-TMLE uses cross-validation and data-adaptive methods to minimise biased point estimates and inference that can arise from model misspecification. Briefly, data are split into so-called training and validation sets. Each a priori-specified algorithm (various parametric regressions or smoothing algorithms) is fit on the training set and its performance evaluated on the validation set. This obtains an ‘honest’ measure of estimator performance and avoids over fitting. The algorithm with the best performance or the best-weighted combination of inputted algorithms is then used to obtain an initial estimate of the conditional probability of linking, given all the predictor variables. Next, these initial estimates are updated to further reduce bias and to obtain valid inference. This targeting step makes use of information in the so-called propensity score (the conditional probability of each predictor, given the remaining predictors). Using information in the propensity score can be especially important when the data are sparse and the outcome is rare. Consequently, C-TMLE is double-robust; it will yield a consistent estimate if either the conditional probability of linking or the propensity score is consistently estimated. Finally, C-TMLE averages over the remaining predictor variables to obtain a marginal estimate of the importance of each predictor on the probability of linking.

Ethics statement

All subjects provided written consent for participation. The study was reviewed and approved by the Makerere University School of Medicine Research and Ethics Committee, the Ugandan National Council on Science and Technology, and the UCSF Committee on Human Research.

Results

The CHC was attended by 4476 persons from Kakyerere parish; of these, 2282 were adults and 2252 (99%; mean/median age 48.5/45 years) were screened for hypertension and answered an epidemiologic survey at the CHC. Seventy-three adults (3.2%) reported current use of antihypertensive medications; 281 adults had high BP on screening (12.5%) and did not report using antihypertensives. Risk factors associated with hypertension included age, gender, BMI, diabetes, alcohol consumption and family history, which have been discussed in a separate study (Kotwani et al. 2013).

During the CHC, 214 of 281 participants eligible for the study received the linkage intervention, forming the study cohort. Due to lapses in staff communication to the participants, 67 persons left the campaign prior to receiving the linkage intervention.

Demographic characteristics of the study cohort are listed in Table 1. Briefly, participants were 47.2% women, mean/median age 51.2/49.5 years, 81.3% employed in manual occupations (mostly farming) and 1.9% HIV positive.

Table 1. Demographic and clinical characteristics of study participants
 N (%)
Total N = 214Linked N = 178Not linked N = 36
  1. a

    N = 213.

  2. b

    N = 213.

  3. c

    N = 208.

Age (years)
18–2923 (10.8)15 (8.4)8 (22.2)
30–4463 (29.4)55 (30.9)8 (22.2)
45–5953 (24.8)46 (25.8)7 (19.4)
≥6075 (35.0)62 (34.8)13 (36.1)
Gender
Women101 (47.2)86 (48.3)15 (41.7)
Men113 (52.8)92 (51.7)21 (58.3)
BMIa
≤25146 (68.5)119 (67.2)27 (75.0)
25–3040 (18.8)33 (18.6)7 (19.4)
≥3027 (12.7)25 (14.1)2 (5.6)
Blood pressure (BP, in mmHg)
Systolic BP Mean (SD)154.5 (15.6)154.9 (15.1)152.8 (18.1)
Diastolic BP Mean (SD)89.6 (12.5)89.6 (12.3)89.5 (14.0)
Severity of hypertension
Stage 1 (140–159/90–99 mmHg)140 (65.4)118 (66.3)22 (61.1)
Stage 2 (≥160/≥110 mmHg)74 (34.6)60 (33.7)14 (38.9)
Occupation
Unemployed25 (11.7)16 (9.0)9 (25.0)
Manual174 (81.3)150 (84.3)24 (66.7)
Sedentary15 (7.0)12 (6.7)3 (8.3)
Education level
None69 (32.2)55 (30.9)14 (38.9)
Primary95 (44.4)79 (44.4)16 (44.4)
Secondary38 (17.8)33 (18.5)5 (13.9)
Tertiary and beyond12 (5.6)11 (6.2)1 (2.8)
Current tobacco user
No176 (82.2)143 (80.3)33 (91.7)
Yes38 (17.8)35 (19.7)3 (8.3)
Alcohol useb (drinks per month)
None111 (52.1)91 (51.4)20 (55.6)
0–1049 (23.0)37 (20.9)12 (33.3)
≥1053 (24.9)49 (27.7)4 (11.1)
HIV
No210 (98.1)175 (93.8)35 (97.2)
Yes4 (1.9)3 (1.7)1 (2.8)
Random blood glucose
0–7176 (82.2)145 (81.5)31 (86.1)
7–1134 (15.9)30 (16.8)4 (11.1)
≥11.14 (1.9)3 (1.7)1 (2.8)
Family historyc
No160 (76.9)132 (75.9)28 (82.4)
Yes48 (23.1)42 (24.1)6 (17.6)
Time to appointment
0–2 weeks60 (28.0)49 (27.5)11 (30.6)
2–3 weeks22 (10.3)18 (10.1)4 (11.1)
3–4 weeks132 (61.7)111 (62.4)21 (58.3)
Appointment site
Regional hospital22 (10.3)17 (9.6)5 (13.9)
Local health center192 (89.7)161 (90.4)31 (86.1)

Linkage to care

Within 6 months, 178 (83%) of the 214 participants who received the linkage intervention (the study cohort) visited a health facility for hypertension management. Data were not available for the 67 persons who did not receive the linkage intervention; assuming none of these individuals linked to care, overall 63% (178/281) linkage was achieved.

Median time to linkage was 22 days (interquartile range: 14–24 days; = 163). Of the 36 participants in the study cohort who failed to link to care, 30 did not seek care while 6 were lost to follow-up (summarised in Figure 2).

Figure 2.

Study schema for the hypertension linkage to care intervention. Two hundred and eighty-one adults from Kakyerere parish were eligible to participate in the study; however, 214 adults received the hypertension linkage to care intervention and formed the study cohort. Within 6 months, 178 (83%) of these persons linked to care. Thirty subjects were determined to have not linked to care while six were lost to follow-up. Persons who did not link were tracked and interviewed to determine barriers to care.

Predictors of linkage to care

Among the study cohort, after multivariate adjustment, independent predictors of linkage to care included age, gender, education, occupation, tobacco use, alcohol consumption, family history and appointment site. Adjusted risk differences (RD) along with 95% confidence intervals (CI) are given in Table 2.

Table 2. k from C-TMLE analysis
 Proportion that linked to care (%)Adjusted Risk Difference, RD (%)95% CIP-value
  1. a

    Significance at the α = 0.05 level (N = 207†).

  2. †Seven observations were removed due to missing data.

Age (years)
18–2915/23 = 65.2RefRefRef
30–4455/63 = 87.319.0−3.4, 41.40.096
45–5946/53 = 86.814.9−8.0, 37.80.202
≥6062/75 = 82.736.915.7, 58.20.001a
Gender
Men92/113 = 81.4RefRefRef
Women86/101 = 85.214.45.2, 23.70.002a
Education
None55/69 = 79.7RefRefRef
Primary79/95 = 83.25.5−5.7, 16.70.335
Secondary33/38 = 86.811.11.6, 20.50.021a
Tertiary and beyond11/12 = 91.719.78.7, 30.8<0.001a
Occupation
Unemployed16/25 = 64.0RefRefRef
Manual150/174 = 86.218.54.6, 32.30.009a
Sedentary12/15 = 80.01.7−14.6, 18.00.840
Current tobacco use
No143/176 = 81.2RefRefRef
Yes35/38 = 92.111.42.4, 20.40.013a
Alcohol (drinks/month)
None91/111 = 82.0RefRefRef
0–1037/49 = 75.5−7.0−20.2, 6.20.299
>1049/53 = 92.411.42.0, 20.70.017a
Family history
No132/160 = 82.5RefRefRef
Yes42/48 = 87.513.05.7, 20.30.001a
Time to appointment
0–2 weeks49/60 = 81.7RefRefRef
2–3 weeks18/22 = 81.88.2−4.4, 20.70.203
3–4 weeks111/132 = 84.1−0.2−11.0, 10.60.965
Appointment site
Regional hospital17/22 = 77.3RefRefRef
Local health center161/192 = 83.843.435.9, 50.9<0.001a
Severity of hypertension
Stage 1118/140 = 84.3RefRefRef
Stage 260/74 = 81.12.7−6.2, 11.60.556

Participants ≥60 years were more likely to link than those aged 18–29 years (RD = 36.9%, 95% CI 15.7, 58.2). There was no statistically significant difference in linkage between those aged 18–29 years, 30–44 years and 45–59 years. Women had a 14.4% greater probability of linking than men (RD = 14.4%, 95% CI 5.2, 23.7). Increasing level of education was associated with an increase in the likelihood of successful linkage. Compared to those with no formal education, persons with tertiary education or beyond were the most likely to link to care (RD = 19.7%, 95% CI, 8.7, 30.8) followed by those with secondary education (RD = 11.1%, 95% CI 1.6, 20.5).

Manual workers, mostly farmers, were more likely to link than the unemployed (RD = 18.5%, 95% CI 4.6, 32.3). Current tobacco use was associated with an increased probability of linkage to care (RD = 11.4%, 95% CI 2.4, 20.4). Subjects with an alcohol consumption of ≥10 drinks per month were also more likely to link than those reporting no alcohol use (RD = 11.4%, 95% CI 2.0, 20.7). Family history of hypertension was a significant predictor of linkage to care (RD = 13.0%, 95% CI 5.7, 20.3). Finally, persons referred to the local health centre were more likely to link than those referred to the regional hospital (RD = 43.4%, 95% CI 35.9, 50.9).

In a separate secondary analysis including the 67 hypertensive persons who did not receive the linkage intervention, results were similar to the primary analysis. Independent predictors of linkage to care included age, gender, education, occupation, tobacco use, alcohol consumption, family history and receiving the linkage intervention (data not shown).

Barriers to care

After tracking, 30 persons were confirmed to have not linked to care. Of these, 27 persons were interviewed and barriers to care assessed; three persons could not be interviewed, and care status was determined by close informants' report. Feeling well (59%), expensive transportation (59%), transportation difficulty/inconvenience (33%), fear of being reprimanded by the clinic staff for missing a scheduled appointment (26%), family obligations (22%) and responsibilities at work (22%) were the most common barriers for not linking to care (Table 3). Notably, no participant cited stigma as a barrier in open-ended interview questions.

Table 3. Barriers to care identified during patient tracking (N = 27)
BarrierNumber of responses
N (%)
Medical19 (70)
I felt well and thought I didn't need care16 (59)
I felt too sick to come to clinic2 (7)
I have taken medicine for hypertension before and it did not help me feel better2 (7)
In the past, I have experienced side effects from antihypertensive medications1 (4)
I didn't want to take drugs forever1 (4)
I was afraid of side-effects from starting new medicines0
I was taking too many pills a day0
I was drinking alcohol0
Access to care17 (63)
Transportation was too expensive 16 (59)
Transportation was too difficult or inconvenient9 (33)
Work and family9 (33)
Work interfered with visiting clinic for review6 (22)
I had family obligations6 (22)
Clinic factor8 (30)
I was afraid clinic staff would scold me for missing appointment7 (26)
The staff is not nice 1 (4)
Inconvenient clinic hours1 (4)
The clinics frequently run out of medications (‘stock- out’)0
The care is not good0
It takes a long time to be seen at the clinic0
The waiting area is not comfortable0
Alternative treatment and advice0
A family member or other important person told me to not go to clinic0
Because I went to someone who tried/is trying to cure me by prayer/religious rituals0
Because I saw/am seeing a traditional healer instead0
Because I saw/am seeing a herbalist/nutritionist instead0
Other6 (22)
I forgot my appointment4 (15)
Other 2 (7)
Declines to answer0

Discussion

High blood pressure is the leading risk factor for global disease burden and estimated to cause more than 9 million deaths per year (Lim et al. 2012). Hypertension disproportionately affects the developing world – 80% of cardiovascular deaths occur in low- and middle-income countries (Yach et al. 2004; Lopez et al. 2006). Africa, in particular, has been noted to have the highest prevalence of hypertension among adults older than 25 years (WHO 2013). Early treatment of hypertension can reduce future complications such as heart disease, stroke, kidney disease and retinopathy. However, a weak care cascade with inadequate screening, failure to link to care and inability to adequately treat chronic disease leads to high morbidity, mortality and lost economic output associated with NCDs such as hypertension in developing nations (Bloom et al. 2011).

We screened 2252 adults during a 5-day multidisease screening campaign in rural Uganda and found that 63% of adults with untreated hypertension successfully linked to care within 6 months. Among the study cohort who received a linkage intervention, 83% linkage was achieved. This study provides the first sound estimate of the efficacy of a linkage to care intervention following community-based hypertension screening in sub-Saharan Africa. Our multidisease screening approach also shows that efforts to scale up HIV testing and linkage at the community level can be successfully leveraged to identify and link persons with NCDs such as hypertension.

Within the context of a chronic care cascade for hypertension, this study illuminates the critical first steps of diagnosis and linkage to care. Our study identifies subpopulations most likely to be lost at the step following diagnosis. These data can inform targeted interventions to prevent loss of patients after community-based screening. Younger (18–29 years) persons were less likely to link to care than those ≥60 years. Although youth were less likely to engage in care, they represent a small percentage of the overall burden of hypertension in this community. On the other hand, men represent a large proportion of the hypertension burden, but were less likely to link to care than women. Interventions focusing on men are needed to enhance linkage from community-based screening campaigns.

Persons with little or no formal education had lower probability of linking to care than those with secondary or tertiary education. This finding emphasises the need for increasing awareness and health literacy surrounding hypertension, perhaps through public health initiatives such as the CHC. Higher linkage observed at the local health centre compared with the regional hospital may be explained by their distance from Kakyerere parish. The local health centre is significantly closer to the community (approximately 5 km) than the regional hospital (approximately 30 km). Distance being an important consideration in a low-income setting where transport can be relatively expensive is understandable.

Interestingly, current tobacco users and persons consuming higher amounts of alcohol (≥10 drinks/month) were more likely to link to care. These persons are perhaps already at an increased risk for complications related to hypertension, such as heart disease and stroke. It is likely that a community-based approach could be successful in reaching out to these high-risk groups. Family history also increased likelihood of linkage to care. Receiving encouragement or perhaps sharing the cost of a journey with a family member may contribute to this finding. Finally, manual labourers (mostly farmers), a large majority of this community, were more likely to link than the unemployed.

Tracking subjects who did not link allowed us to identify important barriers to care faced by rural Ugandans in our pilot study. Transportation expenses and inconvenience were prominent issues, which is consistent with expectations from a rural area with poor roads and accessibility (Goudge et al. 2009). Possible outreach could include decentralised care strategies such as home-based screening and treatment for patients living in especially remote areas. Likewise, feeling healthy or lack of symptoms was another common reason for failure to link. This has been reported previously in the HIV linkage to care literature as well (Govindasamy et al. 2011; Nakigozi et al. 2011). Improving patient education surrounding asymptomatic hypertension seems essential to effectively link patients to care. Fear of being reprimanded by clinic staff was also a barrier to care and has been described as a barrier to retention in care for other diseases (Ware et al. 2013). Sensitisation efforts to promote therapeutic alliances and decrease ‘bad patient’ labelling by healthcare workers are needed in this region.

We included travel vouchers in the linkage intervention, which likely boosted linkage frequency, but to an unknown extent. The amount of this voucher approximated the cost of a one-way journey to the health facilities, and participants were still required to invest significant time and resources in order to link to care. Yet, this small voucher may have reinforced participants' intrinsic motivations to seek care and substantially affected linkage frequency. It is possible that in the absence of travel vouchers linkage frequency may be reduced. Similar studies assessing linkage interventions without a travel voucher would help determine what fraction of linkage to care is attributable to transport reimbursement.

Although this study was population-based, limitations include loss of eligible subjects due to unintended operational deficiencies. Specifically, a temporal delay between receiving a diagnosis of hypertension and obtaining the linkage intervention may have confused some participants and led them to leave the CHC prematurely. Those who did not receive an appointment were more likely to be younger, though there were no significant differences by gender (data not shown). It is possible that the few subjects who did not receive the linkage intervention were also those at higher risk of failing to link. Moreover, as participation in the CHC was voluntary, it is possible that individuals with greater health-seeking tendencies came to the campaign, thereby contributing to the high frequency of linkage to care. Our pilot study included a relatively small number of hypertensive adults (= 214) and results should be interpreted cautiously. With only 36 subjects not linking to care and poor representation of certain predictor variables, estimation with standard logistic regression could result in over-fitting and biased point estimates. To minimise these risks and obtain reliable inference, we used C-TMLE with various penalised regression procedures and provide the first report on predictors of hypertension linkage to care in this region. Finally, given the need for streamlined hypertension screening during the CHC, BP measurement in our study was not in accordance with standard guidelines; however, using the lowest of three measurements, we attempted to minimise misclassification bias resulting from using just a single BP measurement.

Despite these limitations, this study provides much needed insights into linkage to care. So far, limited studies have evaluated the care cascade for NCDs in sub-Saharan Africa. Nurse-led hypertension clinics in Cameroon retained only 14% of patients at 1 year with most dropouts occurring after the initial linkage visit (Kengne et al. 2009). In a similar setting, Labhardt et al. (2010) reported extremely low retention (18%) of hypertension and diabetes patients. Though these few reports on retention in care have shown poor results, they also represent a key opportunity to further evaluate and improve all steps in the chronic care cascade. In fact, in a subsequent trial, Labhardt et al. (2011) reported a significant increase in retention rates at 1 year through low-cost interventions such as treatment contracts and reminder letters for missed appointments.

In conclusion, a linkage strategy following community-based hypertension screening achieved excellent linkage to care (83%); identified young adults, men and persons with low levels of formal education as least likely to link; and revealed transport costs and asymptomatic disease state as barriers to linkage in rural Uganda. However, further work is needed to elucidate the various aspects of the chronic care cascade for hypertension in this region. In the context of an ongoing community-based study in East Africa (NCT01864603), we are in the process of describing retention and re-engagement through all steps in the hypertension care cascade.

Acknowledgements

We thank residents and local leaders of Kakyerere Parish for their tremendous support and participation; staff from the Bwizibwera Health Center IV and Mulago Joint Aids Program (MJAP) for their assistance; and the Ugandan Ministry of Health for donating HIV rapid test kits. Support for this study was provided by NIAID and the National Center for Advancing Translational Sciences. Support for this study was provided by NIH A1069502 and A1051982 (to DVH). PK was supported by NIH TR000144.

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