Dramatically Reduced Death Rate during a Comprehensive Disease Surveillance Program in American Adults of Working Age

The David Drew Clinic Ten-Year Experience

Timothy T. Soncrant, M.D.

Summary. Individuals aged 45-65 who were enrolled over a ten-year period in an aggressive disease detection program at the David Drew Clinic had a death rate 12.8 fold lower than did the overall US population of that age. Participants underwent comprehensive medical surveillance procedures, including extensive blood testing and organ and cardiovascular imaging, administered once or twice per year. For 866 patients and 2,647 patient-years of longitudinal evaluation the actual death rate was 1.1%, compared to the expected population-based death rate of 14% (one in seven). Most of the improvement in death rate was due to early detection of curable conditions, such as imminent heart attack, cancer and impending stroke. It thus appears that most deaths in working-age Americans are preventable.

According to the National Center for Health Statistics¹, 14% of Americans who reach the age of 45 die before age 65. The causes of these deaths are similar to those for the adult American population as a whole; a large majority are due to cardiovascular disease, stroke and cancer. They occur despite access to a conventional medical system that performs and receives reimbursement for limited screenings prescribed by a "standard of care." Many deaths that occur in spite of this surveillance, especially those of younger individuals, are considered to be difficult to predict and, therefore, unavoidable.

Table 1: Participant characteristics

All Ages

Number of participants 1,284

Participant-years 3,172

Ages 45-65

Number of participants 866

Male 566

Female 300

Participant-years 2,647

Male 1,806

Female 839

Ages 45-50 754

Ages 50-55 763

Ages 55-60 679

Ages 60-65 451

But are they unavoidable? Surveillance for occult disease can lead to detection and cure of otherwise lethal diseases. Procedures such as mammography, colonoscopy, and prostate-specific antigen (PSA) testing are routinely employed because they reduce mortality from the conditions they detect. And detection of risk factors for future serious disease (such as elevated LDL cholesterol) can lead to interventions that lower the risk of adverse outcomes. Over the past 30 years, medical science has developed many new potentially life-saving tools for detection of hidden cancers, unanticipated heart disease, and imminent stroke that are not included in the standard of care and hence are not routinely performed. It seems plausible that systematic implementation of those techniques would reduce the number of "unavoidable" deaths.

To examine the effect of aggressive medical surveillance on death rates, The David Drew Clinic began offering a recurring program of sophisticated surveillance techniques designed to detect disease early, and to identify and ameliorate risks for future illness. Participants undergo non-invasive medical testing that is individually customized on the basis of known health issues and family medical history. Diagnostic procedures include physical examination, extensive blood testing, physiologic measurements, genetic evaluation, low-radiation body imaging, and provocative cardiac procedures. They are typically administered annually or semi-annually during 2-4 hour clinic sessions.

During a recent ten-year period the David Drew Clinic, 1,284 participants, encompassing 3,172 participant-years, were studied (Table 1). Of those participant-years, 83% were between the ages of 45 and 65 (866 patients, 2,647 participant-years) and are included in this analysis. Women accounted for 35% of participants and 32% of participant-years.

Table 2: Expected and actual death rates

Age Interval Interval death rate (percent)

  U.S. Population David Drew Clinic

45-50 1.80 0.00

50-55 2.59 0.00

55-60 3.78 0.00

60-65 5.91 1.11

45-65 14.08 1.11

The expected death rate for participants was calculated from United States all-cause mortality data published by the National Center for Health Statistics.¹ The national data are grouped by five-year age intervals. For each five-year interval, the corresponding death rate among clinic participants was calculated by dividing the number of deaths by the number of participant-years and then multiplying by 5 years. Results are shown in Table 2.

The expected death rate for the United States population aged 45-65, based upon national data, is 14.08%, or about one in seven. Among David Drew Clinic participants, the corresponding observed death rate was nearly 13-fold lower, at 1.11% (Figure).

Survival

The substantially lower death rate among David Drew Clinic participants could be due to several factors. They include (a) aggressive disease surveillance, (b) reduction of disease risks by medical intervention or lifestyle counseling, and (c) differences between participants and the general population in initial health status, attitudes and practices. The latter, a selection bias, could potentially be quite large, as participants were not selected at random but instead were self-referred. In order to determine the contribution of disease surveillance to the lower death rate among participants, the medical record of each participant was examined for potentially lethal conditions revealed by early detection strategies. Only those discoveries made by methods other than those prescribed by standard of care were included. (For example, colon cancer discovered via colonoscopy in a participant over the age of 50 was excluded because it would have been identified in ordinary care; colon cancer found by colonoscopy in a low-risk, asymptomatic 45 year old was included.) For each included discovery, the probability of a "life saved" was estimated as the chance that death would have occurred before age 65 minus the chance that death would have been averted with ordinary medical care.

During the study, disease discoveries included a variety of cancers and cardiovascular conditions (Table 3). Appropriate interventions were made in all cases, which were expected to result in cure. No adverse outcome of those treatments, or of surveillance procedures, occurred during the study. Based upon the "life saved" analysis, 60% of the difference between death rates for David Drew Clinic participants and the United States population is attributable to comprehensive disease surveillance. The remaining difference is presumed to be due to interventions to reduce disease risk in more health-conscious and possibly healthier-than-average participants. Due to the design of this study, the relative contributions of these latter factors cannot be accurately determined.

Table 3: Some conditions diagnosed

Cardiovascular

Critical coronary stenosis

(imminent heart attack)

Aortic aneurysm

Subtotal carotid artery stenosis

(impending stroke)

Cancer

Melanoma (skin)

Kidney cancer

Colon cancer

Breast cancer

Thyroid cancer

Pancreatic cancer

Small bowel neoplasia

Testicular cancer

These results demonstrate that regular and comprehensive disease surveillance beyond that typically performed according to the accepted standard of care can dramatically reduce deaths during the latter half of the working lifespan. In this study, the death rate for individuals between the ages of 45 and 65 was reduced from 14% to 1.1%. Most of the difference was due to early detection of diseases that were subsequently cured. Thus, the majority of deaths occurring in this segment of the population appear to be avoidable.

This is, to our knowledge, the first report of a comprehensive medical surveillance program that substantially lowers the death rate in Americans of working age. Several disease detection clinics exist in the United States. Some of those are nationally attended whereas other, usually hospital-based, programs serve local communities. Most clinics have a particular focus, such as cardiovascular health, fitness, nutrition, or lifestyle improvement, and usually do not provide the breadth and intensity of surveillance conducted at the David Drew Clinic.

This study has limitations. First, our experience with individuals outside the 45-65 age group is limited. Nationally, in addition to the 14% of individuals who die between 45 and 65, another 9% die in the five years after age 65. Preliminary analysis of the David Drew Clinic experience shows a trend toward a lower death rate in that older age group, but more data would be required for statistical comparison. Second, the average participant was followed for slightly more than three years, too short a period to expect to demonstrate a benefit of risk reduction strategies. The advantage of those efforts, often initiated in individuals younger than 45, may not be realized for 10-20 years, or perhaps longer.

In our experience, adults of working age underestimate their risk of dying. The 14% death rate for ages 45-65 means that about 1 of every 7 of those individuals will die, a figure much larger than most believe to be true. The misconception may arise in part because individuals regard the risk of death from any individual cause as remote, ignoring the aggregate risk of death from all causes. It is thus particularly noteworthy that a 12.8-fold reduction in deaths was accomplished in this relatively young age group. Were this reduction in death rate applied to the entire United States population aged 45-65, more than 400,000 lives would be saved each year. Because a majority of those individuals are employed, many in higher level and managerial positions, the potential impact on national economic activity seems considerable.

¹ Deaths: National Vital Statistics Reports 54:13. Available at http://www.cdc.gov/nchs/data/nvsr/nvsr54/nvsr54_13.pdf