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Key Findings

CHESS Use Results

CHESS use was heavy. The 116 subjects (including the 9 non-randomly assigned women) used CHESS services 15,966 times, an average of 138 uses per person (more than once per day on average) with a duration of 39 hours each. Over 34% of CHESS use occurred between 9:00 p.m. and 7:00 a.m., when most other services were not open.

Discussion Group accounted for a large part (73%) of this extraordinarily high activity, both because of continuing needs for social support and because of the ongoing prospect of new events and topics. Information and Analysis services together accounted for 23% of all uses, but this still amounted to a use of these services 2.5 days per week throughout the first nine weeks.

While making about as much overall use of CHESS as whites, minorities allocated their use somewhat differently among CHESS services. Minorities used Discussion Group a smaller proportion of their total use than whites, while using Information services more and Problem-Solving services more. Women used CHESS 13% more frequently than men. In particular, they were more likely to use the Information services, especially Ask an Expert. Thus the results suggest possible reversal of traditional use patterns that increase knowledge gaps between races, genders, etc.

Quality of Life Results

Quality of life analyses comparing pre-test with a two-month posttest found CHESS users significantly higher than controls on five of eight dimensions and lower on none. CHESS users reported improved cognitive functioning, more feelings of social support, and leading a more active life, while controls stayed steady or got worse on each of these variables. CHESS users also reported greater improvement than controls in actively participating in their health care, and they reported decreased levels of negative emotions while controls stayed the same. There were no significant differences at any time between the groups for depression, physical functioning, or reported levels of energy.

If CHESS was left in places for only three months, its positive effects mostly disappeared once it was removed. However the results were more encouraging when CHESS was left in the home for six months. These results suggest a longer than 3-month implementation not only continues the beneficial effects while CHESS is in the home, but also has carryover effects after CHESS is removed.

Risk Attitudes & Behaviors Results

CHESS did not significantly change sexual risk behavior, but the six-month implementation did improve attitude toward risk behavior and toward disclosure of HIV status to potential partners after CHESS was removed.

Health Services Utilization Results

CHESS users self-reported number of visits to health care providers, time spent with providers, satisfaction with visits, number of admissions to hospitals and length of stay. We examined CHESS effects on reported utilization of health services and then monetized that effect by using average Madison area charges for the relevant health services.

Outpatient Services

CHESS did not significantly affect the number of visits to ambulatory care providers while CHESS was in the home, but the number of phone contacts increased in the experimental group compared to the controls. Using an average charge figure for each service, the total charges for ambulatory care decreased 17% in the CHESS group compared to a reduction of 7% in the control group, but this effect was not statistically significant.

Three months after removing CHESS, the experimental group had (compared to pre-test) significantly fewer visits to dentists, primary care and alternative care providers, while the significant CHESS effect on number of calls disappeared.

However, when visits occurred, CHESS users spent significantly less time with primary care providers and HIV specialists. Overall, the experimental group's time spend with non-emergency providers decreased 8% while control group time increased 13%. This difference was also significant. Hence, while our ambulatory charge estimates were not significantly different, since those figures are not based on time spent, the intensity of resource utilization was significantly lower in the CHESS group.

Inpatient Services

CHESS also had significant effects on inpatient care. While CHESS was in the home, the average probability of admission in the control group increased 42% versus 16% in the CHESS group. In the three months after CHESS removal, the probability of admission increased another 25% in the control group while it decreased 2% in the CHESS group. However, these results were not statistically significant.

Changes in length of stay were significant. For persons admitted to the hospital, there was a 61% increase in average length of stay in the control group and a 29% reduction in the CHESS group. After CHESS was removed, average length of stay continued to be 35% higher than pre-test levels in the control group and 26% lower in the experimental group. As it turned out, there were pre-test differences between control and experimental groups that make the analysis of this data challenging. The analysis did take these differences into account through covariance, but there is no way to completely remove the effect of those differences.

By combining admission rate and average length of stay, it is possible to estimate the effect of CHESS on the costs of inpatient care. One way to estimate the effect is to argue that while they had CHESS, the experimental group costs went down $148 at the same time that the control group costs went up $457, for a total difference of $605, a difference maintained (at a slightly lower level) even after CHESS was removed.

Because of the pre-test differences, a more conservative approach would be to average the pre-test costs of all subjects, and use this as a basis to compare post-test differences between the two groups. Using this approach, pre-tests costs of $658 per person per month increased during the period of CHESS use by $240 for the controls, but only $10 for the CHESS group, a difference of $230 (which decreases slightly to $174 after CHESS was removed). Averaging the results of these two analyses yields an estimated cost savings of $17 per month during the period of CHESS use and $361 after. These figures are approximately 40% and 33% of the average monthly costs of care of an AIDS patient.

Minority Supplement

Thirty-nine minority individuals were involved in the main CHESS study. Thirty other minority individuals (including 11 intravenous drug users in a methadone treatment center) tried CHESS briefly and gave their reactions.

Prior to using CHESS in the experimental study we found that minorities were much more depressed than whites, and their utilization of health services was higher for primary care, HIV care, emergency care, and dentists, but lower for mental health and other non-HIV specialty care.

Separate outcome analyses for minorities were hampered by the small sample size. However, interactions of experimental condition with minority group status and educational level were not significant. That is, CHESS effects were not significantly larger or smaller for minorities than for whites.

In absolute numbers, although not significant, the experimental group of minorities showed a reduction (relative to the control group) in number of visits to dentists, primary care, mental health, and emergency care while CHESS was in the home. The total number of visits for non-emergency care dropped 17% in the experimental group and increased 8% in the control, while CHESS was in the home. After removal, the reduction compared to pre-test was 42% for the experimental group versus 3% for the control group.

Minorities, not in the experimental study, who tried CHESS felt that with minor modifications (e.g., more personal stories of minorities), CHESS would be ready for use in the minority and intravenous drug user (IVDU) communities.


The AHCPR-funded evaluation of CHESS provided very encouraging results. HIV-positive individuals (including low-income minorities) used CHESS frequently for several months and found it both easy to use and very helpful. CHESS improved quality of life and made use of health services more efficient, but did not affect actual risk behaviors (although attitudes toward risk behaviors changed after extended CHESS use). When CHESS was provided for a longer period (six rather than three months), effects appeared to continue even after the computers were removed. Thus, for HIV-positive individuals, six months or even continuous access to CHESS seems beneficial and desirable.

Estimates of medical costs (primarily affected by length of hospitalization) were lower for subjects having access to CHESS than for controls. This estimated cost savings was substantial and was considerably larger than the costs of providing CHESS services to HIV-positive individuals. However, further studies of CHESS impact on costs of care are needed because of pre-test differences between control and experimental groups, as well as the self-report nature of the data. Toward that end a study was funded by the Agency for Health Care Policy and Research to further examine effects of CHESS on costs of care for people with full-blown AIDS. This second study included aspects of care not addressed in this study (drugs and home care) and enhanced self-report data with data extracted from medical records.


The purpose of this project was to assess the impact of CHESS (Comprehensive Health Enhancement and Support System) on: (1) health service utilization; (2) health status (sometimes referred to as "quality of life"); and (3) risk behaviors of HIV-infected people.


CHESS was evaluated in a randomly assigned experiment with 204 HIV-infected people from Madison and Milwaukee, Wisconsin. The 107 experimental subjects (who were given CHESS for three or six months), and 97 control subjects answered a pre-test and two or three post-tests; the first survey was given two months after installation and the last was given three months after the removal of CHESS. In addition, nine women participated in the first cohort as a pilot test and were not randomly assigned. Besides the outcome variables mentioned above, we also examined use of CHESS and cost of operating CHESS. In addition to the main study, we received a supplemental grant to study the potential of CHESS to meet minority needs. The results of this supplement are reported separately.

Funding Period:
August 1994
Principal Investigators:
David Gustafson Sr., Ph.D