The backbone (including nomenclature) of the following discussion will be organized according to so-called Markov processes. This allows the use of a common-sense framework.
One of the most important goals in a medical system is to intervene early and effectively for all disease processes. To discuss this, I will review “essential” hypertension (“essential” in the medical sense means “unknown origin”, not the equivalent of “necessary”). “BP” will be used for blood pressure.
Picture if you will a sequence of “states” through which a patient who is initially healthy (normotensive) but develops hypertension transitions (noting that a Markov process features, in part, a transition from one state to another).
- healthy, normotensive (normal, no bp elevation)
- elevated bp
- hypertension/high bp, stage I
- hypertension/high bp, stage II
- hypertensive crisis
(The above 5 categories are based on the Joint National Committee 8 conventions although values are not supplied.)
1
Normal
2
Elevated
3
Stage I
4
5
For background, it should be noted that even with normal bp, tissues age as time progresses. However, as our bp rises from normal to increasingly abnormal, the rate of tissue aging increases exponentially.
Please note that one’s bp can be quite elevated but entirely asymptomatic. As one reaches the higher states, a significant amount of damage may be done prior to developing symptoms, i.e. the process is “silent”.
Please note also that even with this very simple listing of states 1 through 5, very powerful concepts arise.
As reviewed, the rate of tissue damage is least on the left and most on the right. With each transition, the damage per unit time goes up exponentially.
As the damage increases, so in parallel does cost to treat.
For example, if the patient transitions from state 1->2 (possibly detected on a routine physical examination), the intervention is often counseling. Sodium intake, weight, exercise, and family history are reviewed and plans made to address each as possible followed by a recheck. This approach is very cost-effective and may well lead to a reversion from state 2->1. Additionally, the patient would be alerted to return more often for bp screening.
However, many people decline to undergo interval screening because of an “if it’s not broken, don’t fix it” mentality. They decline routine wellness screens, unaware that much damage can be done over the decades by diseases such as hypertension silently and asymptomatically. In a sense, this is a tribute to human evolution as so much derangement of health can be tolerated.
The unscreened patient might transition over decades from state 1->2->3->4->5 (finally), hypertensive crisis. Symptoms would drive this patient to seek medical attention due to chest pain, dyspnea, headache, weakness, disorientation, nausea, vomiting and/or several other very unpleasant symptoms. Prior to that, hypertension is largely asymptomatic. In hypertensive crisis, it is likely necessary to go to an emergency room for interval assessment and treatment. This will likely lead to admission to a hospital’s critical care unit. The patient will be evaluated for brain, heart, kidney and all other attendant damage associated with untreated hypertension over decades. Depending on the intensity of symptoms and the severity of damage at presentation, the stay could be quite lengthy and costly. I would estimate that the cost to the patient for presenting at state 5 would be somewhere be more than 100 times more expensive than surveillance and multiyear treatment for advancing to state 2.
As one concrete example of ridiculous cost inefficiency, consider the following: those who lose all renal function from hypertension die without dialysis (not everybody on dialysis arrives there because of hypertension, but the fraction is high). Based on the latest statistics available to me, the cost of dialysis (on Medicare) reaches approximately $100,000/patient/yr. According to the American Kidney Fund, 557,000 Americans are on dialysis. Thus, the total overall cost of care for end-stage renal disease is about $55,700,000,000/yr. In the US, amazingly, instead of funding care for the uninsured and allowing them to address hypertension early and cost-effectively, no funding is available until after the kidneys fail giving the patients a short window to begin dialysis. Once kidneys fail (and the patient races to death), the uninsured patient suddenly becomes eligible for Medicare. In other words, our government policy begins care only after the patient has suffered irreparable harm and needs the costliest of interventions. It could save many billions of dollars/yr every year by intervening “upstream” (my parlance) in the lower (left sided) “states”. Yet, very few programs are set up to discover and engage patients early in the disease process. I acknowledge some early attempts to do so have been introduced but, in several senses, they are not compelling. This is a topic which needs more development (please see part II).