The Quality of Life of Patients With Hypertension

Abstract

The authors evaluated the self‐reported quality of life in patients with systemic arterial hypertension and assessed whether clinicians and normotensive respondents from the general public appreciate the impact that hypertension has on health‐related quality of life. A quality‐of‐life questionnaire was completed by 385 individuals: persons with hypertension (n=188), normotensive persons (n=148), and clinicians (n=49). A utility score, which represents one's self‐perceived health‐related quality of life, was generated for each group by using standardized time tradeoff questionnaires. Quality of life with hypertension was judged to be significantly higher according to affected individuals (mean utility score, 0.980), compared with normotensive persons (mean utility score, 0.948) and clinicians (mean utility score, 0.942), who were asked to assume that they had hypertension (p<0.0005). Clinicians and normotensive individuals tend to overemphasize the impact that hypertension has on quality of life, as compared to affected patients. The relatively low impact that hypertensive individuals indicate high blood pressure has on their quality of life May contribute to their lack of compliance with treatment regimens

Systemic arterial hypertension is a common medical condition that affects more than 50 million people in the United States. ¹ Despite the efforts of physicians to frequently monitor the blood pressure of their patients and despite a wide array of effective antihypertensive medications currently available, many patients continue to suffer significant morbidity and mortality from the long‐term effects of high blood pressure. Considering the known association between elevated blood pressure and risk for cardiovascular and cerebrovascular events, along with various other medical conditions, it is important for researchers and clinicians to understand why some patients have difficulty maintaining their blood pressure within the range of normal.

Hypertension has been termed “the silent killer” because, unlike persons with many other medical conditions, patients with elevated blood pressure can remain asymptomatic for many years and then suddenly suffer a serious adverse event, such as a myocardial infarction or stroke. The challenge for clinicians is to educate asymptomatic patients about the long‐term consequences of sustained hypertension and to motivate patients to regularly follow prescribed medication regimens despite possible side effects and considerable long‐term financial cost.

Numerous investigators have studied the quality of life of patients with systemic arterial hypertension. Considering that quality of life is difficult to define in universally accepted terms, let alone to quantify, to date there is no one survey tool that has been deemed the gold standard to measure quality of life in hypertensive patients. Commonly used tools to measure quality of life have included the 36‐Item Short Form Survey, ² the Nottingham Health Profile, ³ the Symptom Rating Test, ⁴ the Sickness Impact Profile, ⁵ and the Quality of Well‐Being Scale. ⁶ While all of these measures have demonstrated reliability and validity, considerable variation exists in the domains each uses to quantify quality of life. Some researchers have questioned whether standardized instruments such as these can adequately capture the quality of life of all populations of patients suffering from all types of conditions. ⁷

A technique that has been gaining popularity among investigators to quantify quality of life is the time tradeoff method of utility assessment. ⁸ , ⁹ , ¹⁰ , ¹¹ , ¹² , ¹³ , ¹⁴ The time tradeoff technique requires respondents to state the proportion of theoretical remaining years they would be willing to give up in order to live in perfect health. For example, a respondent can be asked to imagine that she is blind and then asked to consider how many years of life she would be willing to trade in exchange for permanently restored, perfect vision. Unlike the traditional quality‐of‐life measures, which need to predict the quality‐of‐life domains that are important for the individuals in a given patient population, this technique enables individuals to decide for themselves which aspects of quality of life are most important. Time tradeoff is especially useful because unlike instruments that quantify quality of life for multiple domains, this instrument generates a summary score, a health status index, which represents the preferences of individuals for a specific health state that can be incorporated into subsequent analyses to determine the cost‐effectiveness of implementing a particular intervention. Like the more traditional quality of life instruments, the time tradeoff technique has demonstrated validity, reliability, and reproducibility. ⁹ , ¹¹

The purpose of the current study was to utilize the time tradeoff method of utility assessment to quantify the quality of life of a group of patients with hypertension. A second goal was to use the time tradeoff technique to assess whether members of the general public who are normotensive and normotensive clinicians who treat hypertensive patients can appreciate the impact that hypertension has on a person's quality of well‐being.

METHODS

Participant Selection

Inclusion criteria for enrollment in this study were age 18 years or older and the ability to read and respond to the self‐administered questionnaire. Three groups of respondents were enrolled in the study: patients with systemic arterial hypertension, members of the general public who denied suffering from hypertension, and health care clinicians. The group of clinicians included third‐ and fourth‐year medical students, house officers, and attending physicians from area medical centers, all of whom regularly treat patients with hypertension and the sequelae of poorly controlled blood pressure. Members of the general public and patients with hypertension were recruited from the community as well as from two of the authors' (GCB and MMB) clinical practices. Prior to consenting to participate, individuals were given a brief explanation of the purpose of the study. This study was approved by the Institutional Review Board of Wills Eye Hospital, Philadelphia, PA.

Health‐Related Quality‐of‐Life Questionnaire

Using the time tradeoff technique of utility assessment, we designed a questionnaire that quantifies respondents' health‐related quality of life. The questionnaire consists of two sections. The first section asks personal and demographic information, including age, gender, and race/ethnicity. It also asks whether the respondent suffers from hypertension or is currently taking antihypertensive medications. In the time tradeoff section, the respondent is asked the following theoretical question:

For the following two‐part question, assume that you are a patient suffering from high blood pressure. Suppose researchers developed a new technology that could permanently cure you of this condition. The technology always works but decreases your survival. Essentially, the treatment theoretically increases your quality of life, but decreases the length of time you live. 1) How many additional years do you think you will live? 2) What is the maximum number of those years, if any, you would be willing to give up if you could receive this technology and be cured forever of this condition?

Respondents recruited from the general public who admitted to employment within the health care industry but did not directly participate in the management of patients with hypertension were eliminated from further analyses to prevent potential confounding. Moreover, clinicians who admitted to having hypertension were eliminated from the subsequent analysis. For those participants who failed to report current age or the oldest age to which they expected to live, utility scores could not be calculated and their data were excluded from our analysis. Moreover, the data from respondents who stated that they expect to live “forever” or for a nonspecific amount of time, such as “80+” years, were also eliminated from the analysis. If respondents expressed the age to which they expected to live as a range, such as “80–90” years, an average of the two outer‐limit values was calculated and used to generate the utility score.

Calculating Utility Scores

By incorporating each participant's stated age, the estimated number of additional years he or she expected to live, and the maximum number of years the respondent would theoretically be willing to forego in order to be permanently cured of hypertension, the time tradeoff technique was employed to generate a utility score for each respondent. The utility score is a representation of the relative desirability of a particular state of health for a specified length of time, as compared to the reference states of death and perfect health. ¹¹ , ¹² , ¹³ , ¹⁴ Utility scores range on an interval scale in which a value of 0.00 represents death and a value of 1.00 represents perfect health. Table I shows the method utilized for our analysis to tabulate utility scores.

Table I.

Sample Calculation of a Utility Score

Respondent's age: 30 years

Age the respondent expects to live to be: 90 years

Response to time tradeoff question (presented in the text): 12 years

Step 1: Determine the number of additional years of life the patient expects to live 90 years−30 years=60 additional years

Step 2: Divide the number of years the respondent is willing to give up to spend the rest of his/her living years free of hypertension from the value obtained in Step 1 12 years/60 years=0.20

Step 3: Subtract the value obtained in Step 2 from 1.0 1.0−0.20=0.80

Interpretation: The respondent is willing to give up 12 of 60, or 20%, of his/her remaining years in a tradeoff for living free of hypertension. The utility score is generated by subtracting the percentage of remaining years traded (0.2 or 20%) from the state of perfect health (1.0 or 100%). This respondent's utility score, representing his/her perception of quality of life with hypertension if 0.8 or 80%

Statistical Analysis

The data were calculated by using SPSS 10.0 for Windows. Descriptive characteristics of the study sample were calculated for the entire cohort and for each of the three groups. Appropriate sample size was determined using Sample Power 2 (SPSS, Chicago, IL). Assuming a two‐sided alpha of 0.05 and a minimum mean difference of 5% in mean utility values among the cells, 30 patients would be required in each group to have a power of 90%. A one‐way analysis of variance (ANOVA) was performed to determine if there was a significant difference between the groups with respect to age, and the chi‐square test was used to evaluate the categorical variables of race/ethnicity and gender. Next, mean utility scores and categorized utility scores were generated for the entire sample and for the groups separately. ANOVA was also used to detect any significant difference among the mean utility scores of the three groups. If a significant difference was detected, the Scheffé method to account for multiple comparisons was employed to determine which group(s) differed significantly from the others. ¹⁴ , ¹⁵ Significance was presumed to occur at the 0.05 level.

RESULTS

A total of 403 respondents filled out the health‐related quality‐of‐life questionnaire. Of these, 18 individuals (4.5%) were not included in our analysis for one of the following reasons: the respondent failed to state the age to which he or she expected to live, or the number of years he or she was willing to trade (n=15); or the respondent was a health care professional who did not treat hypertensive patients (n=3). The proportion of participants not included in the analysis was similar in the normotensive and hypertensive groups. Data from the remaining 385 participants (95.5%) were included in our analysis. Of these participants, 188 persons (48.8%) were currently suffering from hypertension, 148 (38.4%) were members of the general public who denied suffering from hypertension, and 49 (12.7%) were clinicians. Complete demographic data were available for 373 respondents; 54% were women and 87.3% were white.

Table II shows the demographic characteristics for the study sample, stratified by group. There was a significant difference in age between the groups (p<0.0005): hypertensive patients were the oldest (mean, 64.2 years), followed by normotensive persons in the general public (mean, 44.9 years) and then clinicians (mean, 29.7 years). The ethnic/racial makeup of the groups also differed, with the normotensive general public and hypertensive groups having a higher proportion of white persons (p=0.001). When comparing the groups with respect to gender, there was no statistically significant difference between the groups (p=0.147).

Table II.

Demographic Characteristics

Characteristic	General Public (Normontensive)	Clinicians	Hypertensive Patients	p Value
Age (SD)	44.85 (13.61)	29.73 (7.53)	64.17 (11.46)	<0.0005
Race				0.001
White	131 (90.3%)	34 (73.9%)	171 (32.3%)
Other	14 (9.7%)	12 (26.1%)	13 (7.1%)
Sex				0.147
Female	86 (59.7%)	20 (43.5%)	101 (54.0%)
Male	58 (40.3%)	26 (56.5%)	86 (46.0%)

Table III shows the distribution of utility scores for the total sample and for the three groups separately. The overall utility score for the entire cohort of respondents was 0.963. The utility scores (explained in the Discussion section) for normotensive persons in the general public, clinicians, and patients with hypertension were 0.948, 0.942, and 0.980, respectively. ANOVA demonstrated a significant difference in utility scores between the groups. There was no significant difference between the general public and clinicians when the Scheffé method of accounting for multiple comparisons was employed; however, the patient group differed significantly from the normotensive (p<0.0005) and clinician (p<0.0005) groups.

Table III.

Utility Scores by Group

Variable	General Public (n=148)*	Clinicians (n=49)†	Patients (n=188)‡	Total (n=385)	p Value
Mean utility score	0.948	0.942	0.980	0.963	<0.0005
(95% CI)	(0.935, 0.961)	(0.918, 0.967)	(0.971,0.989)	(0.951,0.968)
UTILITY SCORES IN (%)
0–0.40	0(%)	0(%)	0(%)	0(%)
0.40–0.85	17 (11.5%)	5 (10.2%)	10 (5.3%)	32 (8.3%)
0.851–0.95	34 (23.0%)	16 (32.7%)	11 (5.9%)	61 (15.8%)
0.951–0.999	19 (12.8%)	8 (16.3%)	5 (2.7%)	32 (8.3%)
1.00	78 (52.7%)	20 (40.8%)	162 (86.2%)	260 (67.5%)
Total	148 (100.0%)	49 (100.0%)	188 (100.0%)	385 (100.0%)	<0.0005
CI=confidence interval; °not significantly different from clinicians (p=0.856), but significantly different from patients (p<0.0005), using the Scheffe method for accounting for multiple comparisons, †not significantly different from general public (p=0.896), but significantly different from patients (p<0.0005), after using the Scheffe method for accounting for multiple comparisons; ‡significantly different from both clinicians and general public (p<0.0005), after using the Scheffe method for accounting for multiple comparisons

DISCUSSION

Utility analysis was originally designed to assess how individuals make rational decisions when faced with uncertainty. ¹⁶ Recently, investigators have applied this methodology to the field of medicine to appreciate how individuals make difficult decisions regarding their health. Using the time tradeoff method of utility assessment to determine how many years one would be willing to forego to avoid living in a certain state of health helps researchers appreciate the relative desirability of various health states. Individuals' preferences for living with a given state of health compared with others are indicators of quality of life.

Using the time tradeoff method of utility analysis, the mean utility scores for hypertensive patients, normotensive members of the general public, and clinicians in this study were 0.980, 0.948, and 0.942, respectively. This theoretically means that if all 188 respondents with hypertension were to live an additional 1 year, on average, each would give up only 7 days (358/365) to live the rest of his or her remaining 1 year free of hypertension. In comparison, when asked to theoretically assume that they had hypertension, the group of 148 normotensive individuals and the group of 49 clinicians would, on average, be willing to forego 19 (346/365) and 21 (344/365) days, respectively, of an additional year to live the rest of the year free of hypertension.

The mean utility score of 0.980 for the group with hypertension can be compared with published utility scores for other health states. As Table IV shows, the hypertensive patients in our study were willing to give up considerably less time than patients in other published time tradeoff utility analyses for their respective medical conditions. ¹³ , ¹⁷ , ¹⁸ , ¹⁹ , ²⁰ , ²¹ The fact that patients with hypertension opted not to forego much time compared with patients suffering from other medical conditions suggests an attitude of indifference by hypertensive patients about living with high blood pressure. Most hypertensive patients in our study apparently feel unburdened, or bothered little, by a life with hypertension, including the possible side effects or financial costs of long‐term antihypertensive medication use and the requirement of regular physician visits and trips to the pharmacy. Moreover, our findings suggest that the hypertensive patients May be somewhat unconcerned about possible long‐term health complications. Alternatively, they May not fully appreciate the potential for serious future events related to hypertension. Perhaps the tradeoff of time for a cure seems unnecessary to these patients because they are confident in the ability of their medications to prevent long‐term, severe complications of prolonged hypertension.

Table IV.

Utility Score for Various Health States

Study	Health State	Utility Score
Reference State	Perfect Health	1.00
Lalande et al. 17	Class I CHD	0.872 (0.847–0.897)
	Class II CHD	0.718 (0.642–0.794)
	Class III/IV CHD	0.609 (0.443–0.773)
Brown et al 20	AKMD	0.72(0.66–0.78)
Torrance and Feeny 15	Mild angina.	0.9
	Moderate angina.	0.7
	Severe angina	0.5
Sackett and Torance 26	Hospitalized dialysis	0.52
Sarroa et al 28	Severe stroke	0.3
Brown et al 21	Bilateral blindness	0.26
Reference State	Death	0.00
CHD=coronary heart disease; ARMD=age‐related degeneration

Another important aspect of our findings is the significant difference in the attitudes of patients with hypertension compared with members of the general public who are normotensive. Our data suggest that members of the general public May overestimate the burden of living with hypertension. It is unclear why normotensive individuals overestimate the impact of hypertension on quality of life. One possible explanation for this finding May be that the normotensive group comprised mainly healthy individuals who would willingly forego time not to be labeled “sick,” regardless of the specific type of illness that would afflict them. ²² A second explanation is that members of the general public who are normotensive May be uncertain about the range of possible side effects, complications, and costs associated with treating hypertension, and their responses May be driven by a fear of the unknown. Lastly, members of the general public May not appreciate the efficacy of antihypertensive medications.

It is important to recognize that the respondents in the hypertensive group all acknowledge that they have high blood pressure and the majority of them are currently taking antihypertensive medications for blood pressure control. As shown in two large, randomized clinical trials, the Treatment of Mild Hypertension Study (TOMHS) ²³ and the Hypertension Optimal Treatment (HOT) ²⁴ study, lifestyle changes, including weight loss and an increase in physical activity, along with aggressive treatment using antihypertensive medications, lead to a reduction in symptoms resulting from hypertension and an improvement in health‐related quality of life. One can certainly argue that if such respondents were not on antihypertensive medications and thus were frequently experiencing symptoms associated with poor blood pressure control, they would forego more time in a tradeoff to be free of hypertension.

Other investigators have performed similar analyses comparing the preferences of patients who have a specified medical condition with those of members of the general public who do not. Lawrence and colleagues ²² performed an analysis similar to ours on a cohort of 1430 respondents, using the time tradeoff method of utility analysis to compare hypertensive patients with normotensive individuals. These investigators found the mean utility score for the patients with hypertension to be 0.831 (95% confidence interval, 0.811–0.851), compared with 0.879 (95% confidence interval, 0.864–0.894) for the normotensive individuals. In other words, if the respondents with hypertension were told they would only live 1 additional year, they would forego 66 days (299/365) of that year to live the remainder of the year free of hypertension. In comparison, normotensive respondents would forego only 44 days (321/365) to live the remainder of the year free of hypertension. It is unclear why the respondents with hypertension in that study chose to forego more years of life to be free of hypertension than their counterparts in the current study. Moreover, the findings from that study suggest that patients with hypertension forego more time than normotensive individuals, which contrasts with the findings from the current study. Despite the observed disparity in the results from our sample and the Lawrence study, both studies demonstrate that the views of hypertensive individuals about the impact of hypertension on quality of life are not shared by normotensive individuals. A study by Balaban et al. ²⁵ comparing the quality of life of patients with arthritis vs. individuals who do not have arthritis and a study by Nerenz and colleagues (D.R. Nerenz, K. Golob, D.L. Trump, unpublished data, 1990) comparing patients with cancer to members of the general public who do not have cancer found remarkable similarities between the two groups. In contrast to our study and the study by Lawrence, the Balaban and Nerenz studies utilized more traditional quality‐of‐life measures to assess the preferences of their subset populations. It is unknown whether the observed similarities between the patients and the healthy group of respondents would have been observed if the time tradeoff method had been used in those two studies. Moreover, it is quite possible that members of the general public can better appreciate the impact that chronic, debilitating conditions with prolonged symptoms (such as arthritis and cancer) have on quality of life than the impact of an indolent condition, such as hypertension.

The results from this study not only show that normotensive respondents overestimate the impact that hypertension has on quality of life as compared to affected patients, but also demonstrate that the clinicians who care for patients with hypertension are no better than the general public at assessing the well‐being of individuals with high blood pressure. The findings from our analysis are similar to the results of a study by Jachuck et al., ²⁶ who assessed quality of life in 75 patients taking antihypertensive medications. They found that although 100% of the doctors believed the quality of life of their patients improved after initiation of therapy with antihypertensive medications, only 48% of the patients reported an improvement in quality of life. Furthermore, 98% of the patients' relatives/companions in that study believed that their significant others' quality of life had deteriorated after they started using antihypertensive medication.

This observed discrepancy between the preferences of clinicians and patients has also been demonstrated for medical conditions other than hypertension, such as multiple sclerosis, ²⁷ depression, ²⁸ total hip arthroplasty, ²⁹ and macular degeneration. ³⁰ Among the possible explanations for the observed differences in utility scores between the clinician and patient groups is the fact that clinicians are continually exposed to patients who have developed the long‐term consequences of uncontrolled hypertension and thus May be able to better appreciate what one's quality of life May be after suffering a related adverse event, such as a myocardial infarction or stroke. Clinicians also prescribe antihypertensive medications on a regular basis and are aware of the full range of side effects these medications can cause. Another plausible reason for the observed disparity between the utility scores of hypertensive patients and clinicians is that clinicians May believe that the current antihypertensive medications have a limited effect on reducing morbidity and mortality associated with hypertension. Lastly, patients who do not experience adverse effects from the condition or the medications used to control it presumably are less likely to spend precious moments during their brief office visits discussing their hypertensive condition. Conversely, the concerns and complaints of patients who experience complications related to their hypertensive condition or the medications taken to manage it would more likely be vocalized. The opinions of physicians regarding hypertension May therefore be formed in part by a bias in their clinical experience in favor of disproportionately negative feedback from their patients with hypertension.

As with any study, there are potential inherent weaknesses in the present study. Some investigators critical of using the time tradeoff technique to assess quality of life have questioned whether humans are able to adequately integrate complex probability information when making decisions that involve risk. ³¹ Despite such criticisms, the time tradeoff method of utility assessment has been found to demonstrate validity, reliability, and reproducibility, and it serves as an appropriate means of assessing the relative importance of various health states. ⁹ , ¹¹

A potential source of bias in this study is the difference in age between the hypertensive group (mean, 64.2 years) and the normotensive respondents (mean, 44.9 years) and clinicians (mean, 29.7 years). The group of clinicians included third‐ and fourth‐year medical students and house staff, who lowered the average age for this group. Moreover, individuals with known hypertension tend to be older, since it often takes years after onset before one experiences and seeks care for symptoms of high blood pressure. However, when comparing the mean utility scores for the normotensive respondents who are younger than age 50 years (0.939) to the utility scores of those older than 50 years (0.952), there is little difference between the groups, and the utility scores for both groups are lower than those for the corresponding age‐stratified subgroups of hypertensive respondents.

Regarding the differences in age noted above, since the time tradeoff utility score represents the proportion of years traded to the total remaining years, this instrument can be used to accurately compare responses among respondents of various ages. For example, trading 10 years of one's life for better vision means something completely different for a person 18 years of age than for someone 90 years of age. If both the 18‐year‐old and the 90‐year‐old state that they expect to live to be 110 years of age, the utility score generated for each would be different, as shown below:

Respondent age: 18 years; age to which respondent expects to live: 110 years; number of years willing to trade for better vision: 10 years

110−18 = 92

1 − (10/92) = 0.891 (utility score)

Respondent age: 90 years; age to which respondent expects to live: 110 years; number of years willing to trade for better vision: 10 years

110−90 = 20

1 − (10/20) = 0.50 (utility score)

We would expect those who are older to trade fewer remaining years than younger individuals, who have more remaining years to trade.

A second possible source of bias is the significant difference in the racial/ethnic makeup of the clinician group (73.9% white) vs. the normotensive (90.3% white) and hypertensive (92.9% white) groups. Considering that a significant number of people with hypertension are African American, and noting that this and other nonwhite populations are poorly represented in the current sample, further studies will be needed to determine whether race/ethnicity affects preferences regarding hypertension and quality of life.

Despite the shortcomings mentioned above, we believe that the current analysis demonstrates that there is a disparity between the preferences of those with hypertension, as compared to normotensive individuals and clinicians who care for hypertensive patients. We believe this information offers clues as to why many individuals with hypertension minimize the significance of the disease and its effects, which in turn May contribute to difficulties with hypertension treatment compliance. ³² , ³³ Based on the findings in this study, we feel it is crucial for clinicians who manage patients with systemic arterial hypertension to routinely reassess compliance of their patients and include appropriate education and reinforcement in their care.

Acknowledgments: This work was supported in part by the Retina Research and Development Foundation, Philadelphia, PA; the Volunteer Faculty Research Award, Jefferson Medical College, Philadelphia, PA; the Principal's Initiative Research Grant, Kingston, Ontario, Canada; and the Premier's Award for Excellence, Ottawa, Ontario, Canada. The authors are grateful to Diana Coren for invaluable logistic support.