Telephone Self-management Interventions for BP Control
The HINTS trial used a 4-group design to evaluate the impact of home BP monitoring and telephone-based interventions on patients with inadequate BP control. Study participants were primary care patients in Durham Veterans Affairs Medical Center (VAMC) general internal medicine clinics, diagnosed with hypertension, used BP lowering medication, and—based on recorded BP in electronic medical records—had inadequate BP control (>140/90 mm Hg) over the prior 12 months. A total of 591 patients were randomized into one of the trial's 4 intervention arms (Table I). The HINTS participants had a mean age of 64 years, half were African American, and 92% were male. Completion rates at 18 months were similar across groups (83%-89%).
Details of the study design and the interventions have been reported elsewhere. Briefly, patients who were randomly assigned to an intervention arm received a home BP monitor and telemedicine device to transmit BP measurements. Patients were provided with approximately 10 minutes of training on use of the device and were asked to obtain BP readings every other day (at least 3 readings per week). Intervention was triggered if 2-week average measurements of BP were not in control (≥135/85 for nondiabetic patients and ≥135/80 for diabetic patients). Patients who maintained adequate BP control did not activate intervention but triggered nurse contact every 6 months to reinforce their positive behavior.
If home BP control was inadequate in the behavioral intervention, the nurse contacted patients by telephone and administered tailored, patient-specific, and prescripted modules that focused on improving hypertension self-management behaviors. Modules addressed topics such as hypertension knowledge and adverse effects of antihypertensive medication and evidence-based recommendations regarding salt intake, weight, stress reduction, smoking cessation, and alcohol use. In the medication management intervention, a nurse notified a study physician and provided the physician with a medication change recommendation based upon a standardized evidence-based protocol and decision support tool. The study physician consulted with the nurse to review the patient's BP, medication, and adherence and discussed changes in hypertension medication. The nurse communicated recommended changes to the patient by telephone, and the study physician electronically prescribed the medication and generated a note in the patient's medical record. In the combined intervention, the nurse initially addressed recommended medication adjustments followed by tailored behavioral intervention, described above. For patients in usual care, disease management took place in traditional clinic settings, with no home telemonitoring equipment and no contact with intervention nurses.
The primary outcome of the study was BP measured at baseline and 6, 12, and 18 months (Table II). Patients in the behavioral management and medication management arms showed significant improvement in BP control at 12 months; compared with usual care, BP control improved 12.8% and 12.5%, respectively (P < .05). Blood pressure control also improved 8.3 percentage points for patients in the combined intervention group, but this change was not statistically significant (P > .10). At 18 months, only the combined group showed evidence of improved BP control relative to usual care, although this was not statistically significant (7.7%, P > .10).
Intervention costs and direct VA medical costs over 18 months comprised total costs. The economic evaluation was performed from the perspective of the VA health care system.
Intervention costs over the 18 months of the intervention were aggregated across 3 main categories: home BP monitoring, intervention startup, and intervention personnel (Table III).
Variable costs per patient for BP monitoring included costs for the monitor and telemedicine device to transmit BP measures ($550), batteries for the intervention period ($9.61), and medication containers ($2.17).
Start-up costs were allocated equally across the 3 treatment arms and included 2 laptop computers and cases ($2,000 and $189 each, respectively) for nurses' administration of the interventions. We assumed no overhead costs associated with the intervention because neither additional space nor office equipment was required to integrate these activities into routine care. Likewise, associated costs for the development and maintenance of the intervention's decision support software for this project were considered to be a part of usual clinic care in the VA system and were thus not included in cost calculations.
Intervention personnel comprised most intervention costs. The primary cost component of HINTS was compensation for the 2 registered nurses (1.9 full-time equivalent) who administered the 3 intervention arms over the 18-month trial period. Nurse salary and fringe totaled $90,559 per full-time equivalent based on the federal nurse pay schedule for a grade 2 registered nurse working a 40-hour week at Durham VAMC. We attributed nurses' entire full-time salary and fringe to intervention costs to simulate real-world clinical practice, as nurses administered the intervention program and performed existing clinic duties. In this article, we conservatively estimate nurse costs, although clinic time not devoted to the BP control program would be absorbed in medical center funds if the intervention was implemented in clinical practice. Fixed nurse time costs included 75 hours of intervention training and time spent pilot testing intervention protocols. Variable nurse time intervention costs included the costs of the time nurses spent on the telephone, wherein nurses tracked call frequency and time spent on telephone encounters with patients for delivering the scripted intervention and for troubleshooting. Calls <1 minute in duration (ie, unanswered calls and leaving messages) were excluded. We also assessed nurse preparation and documentation time by call frequency and intervention arm. Nurses spent 10 minutes before each call to patients in the behavioral arm. For patients in the medication and combined intervention arms, nurses prepared 10 minutes before calls and documented medical records 5 minutes after each call. Costs associated with nurse call times were derived from total call time (in hours) and average hourly nurse wage, including fringe.
Variable costs associated with physician time included medical chart review and consultation with nurses for the medication management and combined interventions. Physician time was directly measured over a 35-day period at the height of the study, and the amount of time spent per patient was extrapolated over the entire 18-month intervention period for patients in the medication management and combined intervention arms. The behavioral arm did not require physician time.
Health care use and direct VA medical costs financed and provided by VA at 18 months were drawn from VA administrative files. Data from the VA Decision Support System (DSS) National Data Extract inpatient, outpatient, and pharmacy files were used to generate counts of and costs associated with outpatient and inpatient care as well as outpatient prescription medications filled in the VA system in the 18-month period after participation in the HINTS. Inpatient care included all costs associated with a hospital stay, including inpatient pharmacy costs, laboratories, and tests. For outpatient care, we defined primary care as visits coded to any VA primary care outpatient clinic, including general internal medicine, geriatric clinic, women's clinic, and other screening or preventive care. Outpatient specialty care consisted of visits to outpatient specialty and surgery clinics. Other outpatient care included mental health, ancillary (eg, laboratory or radiology), and emergency department care. To avoid duplication of pharmaceutical costs, outpatient drug costs included in the outpatient cost totals in the DSS outpatient files were removed from outpatient visit cost calculations. Costs of outpatient medications were assessed using the DSS Pharmacy National Data Extract and calculated for all prescription fill costs and hypertension-specific prescription fills (ie, drugs in hypertension drug classes). All outpatient, inpatient, and outpatient pharmacy costs were aggregated to obtain total VA medical costs.
To assess differences in clinical outcomes, we used a logistic mixed-effects regression model to estimate differences in BP control at each time point for each of the intervention groups relative to usual care. Marginal effects and corresponding CIs for the proportion in BP control for each intervention and usual care group at 12 and 18 months were calculated to estimate the relative change in proportion of BP control. To evaluate the effects of the intervention on health care use and direct medical costs, we used χ tests to compare the proportion of patients hospitalized and Kruskal-Wallis tests to compare median number of patients' outpatient encounters between the intervention groups and usual care group. Because direct medical costs were highly skewed for total VA medical care costs, we used nonparametric bootstrapping methods calculating bias-corrected 95% CIs to compare estimates of total costs between intervention and usual care groups.
We conducted several sensitivity analyses to determine costs under different scenarios of implementation. First, we conducted subgroup analysis to examine differences in costs among patients who were in and out of BP control at baseline. Second, we considered a discount on BP monitoring equipment costs, replacing the $550 telemonitoring equipment (ie, monitor and data transmission devices) with a $50 home BP monitor. Third, we assumed that nurse administration of the intervention was a routine job duty and discounted nurse training costs from intervention costs. Lastly, we combined the BP monitoring and nurse training discounts to calculate intervention costs.
This study was approved by the Institutional Review Board of Durham VA Medical Center (VAMC). The authors are solely responsible for the design and conduct of this study, the drafting and editing of this manuscript, and its final contents.
Methods
Intervention: HINTS
The HINTS trial used a 4-group design to evaluate the impact of home BP monitoring and telephone-based interventions on patients with inadequate BP control. Study participants were primary care patients in Durham Veterans Affairs Medical Center (VAMC) general internal medicine clinics, diagnosed with hypertension, used BP lowering medication, and—based on recorded BP in electronic medical records—had inadequate BP control (>140/90 mm Hg) over the prior 12 months. A total of 591 patients were randomized into one of the trial's 4 intervention arms (Table I). The HINTS participants had a mean age of 64 years, half were African American, and 92% were male. Completion rates at 18 months were similar across groups (83%-89%).
Details of the study design and the interventions have been reported elsewhere. Briefly, patients who were randomly assigned to an intervention arm received a home BP monitor and telemedicine device to transmit BP measurements. Patients were provided with approximately 10 minutes of training on use of the device and were asked to obtain BP readings every other day (at least 3 readings per week). Intervention was triggered if 2-week average measurements of BP were not in control (≥135/85 for nondiabetic patients and ≥135/80 for diabetic patients). Patients who maintained adequate BP control did not activate intervention but triggered nurse contact every 6 months to reinforce their positive behavior.
If home BP control was inadequate in the behavioral intervention, the nurse contacted patients by telephone and administered tailored, patient-specific, and prescripted modules that focused on improving hypertension self-management behaviors. Modules addressed topics such as hypertension knowledge and adverse effects of antihypertensive medication and evidence-based recommendations regarding salt intake, weight, stress reduction, smoking cessation, and alcohol use. In the medication management intervention, a nurse notified a study physician and provided the physician with a medication change recommendation based upon a standardized evidence-based protocol and decision support tool. The study physician consulted with the nurse to review the patient's BP, medication, and adherence and discussed changes in hypertension medication. The nurse communicated recommended changes to the patient by telephone, and the study physician electronically prescribed the medication and generated a note in the patient's medical record. In the combined intervention, the nurse initially addressed recommended medication adjustments followed by tailored behavioral intervention, described above. For patients in usual care, disease management took place in traditional clinic settings, with no home telemonitoring equipment and no contact with intervention nurses.
The primary outcome of the study was BP measured at baseline and 6, 12, and 18 months (Table II). Patients in the behavioral management and medication management arms showed significant improvement in BP control at 12 months; compared with usual care, BP control improved 12.8% and 12.5%, respectively (P < .05). Blood pressure control also improved 8.3 percentage points for patients in the combined intervention group, but this change was not statistically significant (P > .10). At 18 months, only the combined group showed evidence of improved BP control relative to usual care, although this was not statistically significant (7.7%, P > .10).
Cost Evaluation
Intervention costs and direct VA medical costs over 18 months comprised total costs. The economic evaluation was performed from the perspective of the VA health care system.
Intervention Costs
Intervention costs over the 18 months of the intervention were aggregated across 3 main categories: home BP monitoring, intervention startup, and intervention personnel (Table III).
Home BP Monitoring
Variable costs per patient for BP monitoring included costs for the monitor and telemedicine device to transmit BP measures ($550), batteries for the intervention period ($9.61), and medication containers ($2.17).
Intervention Startup
Start-up costs were allocated equally across the 3 treatment arms and included 2 laptop computers and cases ($2,000 and $189 each, respectively) for nurses' administration of the interventions. We assumed no overhead costs associated with the intervention because neither additional space nor office equipment was required to integrate these activities into routine care. Likewise, associated costs for the development and maintenance of the intervention's decision support software for this project were considered to be a part of usual clinic care in the VA system and were thus not included in cost calculations.
Intervention Personnel
Intervention personnel comprised most intervention costs. The primary cost component of HINTS was compensation for the 2 registered nurses (1.9 full-time equivalent) who administered the 3 intervention arms over the 18-month trial period. Nurse salary and fringe totaled $90,559 per full-time equivalent based on the federal nurse pay schedule for a grade 2 registered nurse working a 40-hour week at Durham VAMC. We attributed nurses' entire full-time salary and fringe to intervention costs to simulate real-world clinical practice, as nurses administered the intervention program and performed existing clinic duties. In this article, we conservatively estimate nurse costs, although clinic time not devoted to the BP control program would be absorbed in medical center funds if the intervention was implemented in clinical practice. Fixed nurse time costs included 75 hours of intervention training and time spent pilot testing intervention protocols. Variable nurse time intervention costs included the costs of the time nurses spent on the telephone, wherein nurses tracked call frequency and time spent on telephone encounters with patients for delivering the scripted intervention and for troubleshooting. Calls <1 minute in duration (ie, unanswered calls and leaving messages) were excluded. We also assessed nurse preparation and documentation time by call frequency and intervention arm. Nurses spent 10 minutes before each call to patients in the behavioral arm. For patients in the medication and combined intervention arms, nurses prepared 10 minutes before calls and documented medical records 5 minutes after each call. Costs associated with nurse call times were derived from total call time (in hours) and average hourly nurse wage, including fringe.
Variable costs associated with physician time included medical chart review and consultation with nurses for the medication management and combined interventions. Physician time was directly measured over a 35-day period at the height of the study, and the amount of time spent per patient was extrapolated over the entire 18-month intervention period for patients in the medication management and combined intervention arms. The behavioral arm did not require physician time.
Health Care Use and Direct Medical Costs
Health care use and direct VA medical costs financed and provided by VA at 18 months were drawn from VA administrative files. Data from the VA Decision Support System (DSS) National Data Extract inpatient, outpatient, and pharmacy files were used to generate counts of and costs associated with outpatient and inpatient care as well as outpatient prescription medications filled in the VA system in the 18-month period after participation in the HINTS. Inpatient care included all costs associated with a hospital stay, including inpatient pharmacy costs, laboratories, and tests. For outpatient care, we defined primary care as visits coded to any VA primary care outpatient clinic, including general internal medicine, geriatric clinic, women's clinic, and other screening or preventive care. Outpatient specialty care consisted of visits to outpatient specialty and surgery clinics. Other outpatient care included mental health, ancillary (eg, laboratory or radiology), and emergency department care. To avoid duplication of pharmaceutical costs, outpatient drug costs included in the outpatient cost totals in the DSS outpatient files were removed from outpatient visit cost calculations. Costs of outpatient medications were assessed using the DSS Pharmacy National Data Extract and calculated for all prescription fill costs and hypertension-specific prescription fills (ie, drugs in hypertension drug classes). All outpatient, inpatient, and outpatient pharmacy costs were aggregated to obtain total VA medical costs.
Statistical Analysis
To assess differences in clinical outcomes, we used a logistic mixed-effects regression model to estimate differences in BP control at each time point for each of the intervention groups relative to usual care. Marginal effects and corresponding CIs for the proportion in BP control for each intervention and usual care group at 12 and 18 months were calculated to estimate the relative change in proportion of BP control. To evaluate the effects of the intervention on health care use and direct medical costs, we used χ tests to compare the proportion of patients hospitalized and Kruskal-Wallis tests to compare median number of patients' outpatient encounters between the intervention groups and usual care group. Because direct medical costs were highly skewed for total VA medical care costs, we used nonparametric bootstrapping methods calculating bias-corrected 95% CIs to compare estimates of total costs between intervention and usual care groups.
Sensitivity Analysis
We conducted several sensitivity analyses to determine costs under different scenarios of implementation. First, we conducted subgroup analysis to examine differences in costs among patients who were in and out of BP control at baseline. Second, we considered a discount on BP monitoring equipment costs, replacing the $550 telemonitoring equipment (ie, monitor and data transmission devices) with a $50 home BP monitor. Third, we assumed that nurse administration of the intervention was a routine job duty and discounted nurse training costs from intervention costs. Lastly, we combined the BP monitoring and nurse training discounts to calculate intervention costs.
This study was approved by the Institutional Review Board of Durham VA Medical Center (VAMC). The authors are solely responsible for the design and conduct of this study, the drafting and editing of this manuscript, and its final contents.