If you have high blood pressure or high cholesterol, take your medicine regularly as prescribed and don't stop on your own

High value
Evidence A
Buys life
Costs a little
Takes minutes
Some willpower

In plain words

For every 10 mmHg drop in blood pressure, the chance of death falls about 13% and stroke about 27%. Each 1-unit drop in LDL cholesterol on a statin lowers the chance of death by about 10%. People who take their medicine on schedule have a 30% to 45% lower chance of death than people who often miss doses.

Cost: Blood pressure pills and statins bought through volume-based procurement (集采) cost a few to a few dozen CNY a month. You take them once a day, which takes little time. The hard part is that you keep taking them for good, and don't stop because you feel fine.
What you get: Pooling several randomized trials: for every 10 mmHg drop in systolic pressure, the risk of death is about 13% lower (RR 0.87). Systolic pressure is the higher of the two numbers in a blood pressure reading. Major cardiovascular events are about 20% lower (RR 0.80). Stroke is about 27% lower (RR 0.73). Heart failure is about 28% lower (RR 0.72). Statins lower low-density lipoprotein cholesterol (LDL). For every 1.0 mmol/L drop in LDL, the risk of death is about 10% lower (RR 0.90). The same drop lowers major vascular events by about 22% (RR 0.78). In addition, pooling several follow-up studies (observational, not assigning groups), people who took their medicine as prescribed at 80% or more had a lower risk of death than people who often missed doses. For statins it was about 45% lower (RR 0.55). For blood pressure drugs it was about 29% lower (RR 0.71).
Notes: Only people whom a doctor has judged should take medicine should follow this; healthy people don't need it. The “keep taking it” numbers come from follow-up studies, and people who manage to keep taking medicine are also more disciplined in general, so the benefit is overstated. The two sets of randomized-trial numbers earlier are more reliable. This section has no separate item on controlling blood sugar: the evidence that pushing blood sugar lower reduces overall deaths is not as consistent as it is for blood pressure and cholesterol.
Evidence grade: A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.
Sources: Ettehad D 等 (2016). Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis. Lancet. https://doi.org/10.1016/S0140-6736(15)01225-8
Cholesterol Treatment Trialists' (CTT) Collaboration (2010). Efficacy and safety of more intensive lowering of LDL cholesterol: a meta-analysis of data from 170 000 participants in 26 randomised trials. Lancet. https://doi.org/10.1016/S0140-6736(10)61350-5
Chowdhury R 等 (2013). Adherence to cardiovascular therapy: a meta-analysis of prevalence and clinical consequences. European Heart Journal. https://doi.org/10.1093/eurheartj/eht295

Mentioned in

The longer you work night shifts, the higher your cardiovascular risk; if you can move to another position, do it sooner

Translated from the Chinese original. Original book, section 2, tip 12. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer