In vascular realms where risks abide,
A rule we held, a trusty guide,
For every year with diabetes crowned,
A year to age, our wisdom found.
Yet, a study bold, a truth unfurled,
Challenges the norm.
Does having diabetes make you older?
During my tenure as a practicing vascular surgeon, we adhered to a pragmatic guideline to gauge an individual's "biological" age compared to their chronological one. Specifically, for patients grappling with diabetes, a common and challenging condition, we implemented a rule of thumb: for each year a patient had lived with diabetes, we would add a year to their chronological age when “calculating” their operative risk. According to a new study, that was an overestimate – chalk it up to an abundance of caution.
Gompertz’s Law of Mortality
The genesis of our approach finds resonance in the work of Benjamin Gompertz, a self-taught mathematician whose career trajectory took him from the London Stock Exchange to the role of actuary at the Alliance Assurance Company calculating the rates for life insurance policies. His seminal contribution, Gompertz’s Law of Mortality, remains a cornerstone in demographic analysis and actuarial science. Stripping away its complex mathematical underpinnings, Gompertz's law posits an exponential increase in the human mortality rate with advancing age. [1] The question at hand for the researchers was whether individuals with diabetes obeyed Gompertz’s law.
The researchers used data on the “excess” mortality of adults with diabetes in Germany, a country where, as you might suspect, record keeping is critical. Much like my previously mentioned rule of thumb, the researchers defined “diabetes age” as the number of additional years of mortality risk added to that individual’s chronological age.
Individuals with diabetes have a greater mortality rate than individuals without diabetes. In other terms that have about a 62% chance of dying sooner than a comparable individual without diabetes. In chronological terms, a 60-year-old patient with diabetes has the same mortality risk as a 67-year-old – a seven-year gap. As you can see from the graphic, that gap narrows as we age further, presumably because other co-morbidities play increasingly significant roles.
The study has limitations: it doesn’t differentiate individuals with Type I from Type II diabetes and only looks at a year of mortality data. From a clinical standpoint, these findings underscore the imperative of a holistic approach to patient care. While the study may not directly inform surgical decision-making, it underscores the importance of meticulous preoperative evaluation. From a practical standpoint, we can ensure that glucose regulation is under reasonable control before and during surgery. We can also evaluate diabetes fellow traveler coronary artery disease, identifying those who might benefit from a cardiac “tune-up” before surgery.
[1] For those who just must know, here is the formula: “where μ(x) denotes the mortality rate, that is, the hazard of death at age x, and α and β are constants that can be estimated from reported life tables or other survival information.”
Source: Mortality of type 2 diabetes in Germany: additional insights from Gompertz models Acta Diabetologica DOI: 10.1007/s00592-024-02237-w
