The effectiveness of disease prevention

Medical progress is currently one of the strongest forces shaping populations and their health. For instance, an acute heart attack has evolved from being nearly always fatal in the past to having a much higher survival rate today. Researchers at the MPIDR and the Karolinska Institute in Stockholm, Sweden, have examined how disease prevention has affected various diseases in Sweden.

The study was published in the journal The Lancet Regional Health – Europe.

The researchers analyzed Swedish registry data to identify new cases of heart attacks, strokes, hip fractures and malignant cancers. For individuals ages 60–90, the researchers calculated age-specific incidence rates, as well as the proportion of survivors one and five years after diagnosis. They also determined the prevalence—that is, the proportion of people with the disease—at ages 70, 80 and 90. The calculations were based on birth cohorts from 1904–1960 that were observed from 1987–2022.

Advances in prevention and improved treatment following diagnosis

“The patterns of change in incidence and survival are disease-specific. For heart attacks, strokes and hip fractures, the declines in incidence have outpaced improvements in survival. This means that advances in preventing severe acute events are so significant that they result in a decreasing prevalence of these diseases in the population,” explains Anna-Kathleen Piereth, a researcher and Ph.D. student at the MPIDR and the Karolinska Institute.

For example, the incidence rate of heart attacks among 75-year-old women halved over a 20-year period, from those born in 1920 to the 1940 cohort. At the same time, the proportion of survivors one year after diagnosis increased by nearly 50%—from 51% in the 1920 cohort to 75% in the 1940 cohort.

However, the situation is different for malignant cancers. Here, the number of new cases is rising. At the same time, survival proportions have improved significantly in recent decades as cancer diagnosis and treatment have become more effective.

As a result, the prevalence of the disease in the population has increased substantially. While 17.3% of men in the 1912 birth cohort were diagnosed with cancer between ages 80 and 89, this figure increased to 20.7% in the 1931 birth cohort—a rise of about one-fifth.

“Our results suggest that medical progress has been greatest in the prevention of heart attacks, strokes and hip fractures, while for cancer, it has been especially effective in diagnosis and subsequent treatment,” said Piereth.

The disease burden of the Swedish population, which represents a low-mortality population, has shifted. Severe acute events have been prevented more often, while cancer cases have risen and can be treated more effectively.

Although there are differences between countries in the implementation of preventive innovations, the distribution of risk factors and the health care systems themselves, the findings for Sweden may be generalized.

“Because high-income countries share similar medical knowledge, we assume that our findings can serve as a benchmark for understanding trends observed in other populations with low mortality, even if they are at a different stage of development than Sweden.”

New disease histories are changing care needs

“The results show, for the first time, which force—disease prevention or disease management—has had a stronger impact on disease prevalence and how their combined effect, which we refer to as the incidence-survival gap, has altered population health and population composition,” explains Piereth.

The researchers emphasize that the shift in disease burden is changing individual disease histories. “Integrated care approaches are becoming increasingly important to effectively address complex disease histories from an interdisciplinary, cross-sectoral and patient-centered perspective,” says Piereth.

Who’s behind this story?

Sadie Harley

BSc Life Sciences & Ecology. Microbiology lab background with pharmaceutical news experience in oil, gas, and renewable industries.

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Alexander Pol

PhD nano-engineering from Delft University. Published researcher and journal reviewer. Brings scientific insight to content standards.

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