Introduction

No sooner have we digested the importance of not stopping high blood pressure medication (because of the increased risk of stroke), along comes a similar warning, this time for statins. HMG-CoA reductase inhibitors (called 'statins') are safe and effective drugs that lower blood cholesterol levels (chiefly the low-density lipoprotein, or LDL-cholesterol), and in this way help reduce the likelihood of events like heart attack or stroke. It's been noted, however, that statins also have protective effects in people without raised blood cholesterol levels. That is to say, they seem to have useful actions other than just lowering cholesterol. This may be because statins also acts on the cell layer lining the small arteries, helping to prevent clot formation.

A study has just been reported on the effects of stopping statin treatment in patients at risk of a heart attack; the findings seem to relate to this second effect of statins, i.e. their action on the blood vessel lining.

What was done?

Results were analyzed from a large clinical trial of coronary artery disease patients hospitalized with chest pain at rest or worsening chest pain in the previous 24 hours.¹ Patients were given one or other of two clot-preventing drugs. The number of deaths and non-fatal heart attacks (myocardial infarction or MI) were counted at 48 hours, 7 days and 30 days. Medical records supplied information on statin treatment particulars.

There were 1,616 patients in the study. 47 died and 65 had heart attacks within 30 days after hospitalization.

The analysis results

Three patient groups were created: those not taking a statin drug on hospitalization (1,249 patients), those taking a statin (379), and those who had been taking a statin but stopped it after entering hospital (86). Most of those on statins took simvastatin (50%), followed by lovastatin (24%) pravastatin (20%), and fluvastatin (5%). Those taking statins had cholesterol levels about 10% lower than those not taking them.

Those patients who continued on statins after hospitalization had significantly fewer 'cardiac events' (deaths plus non-fatal heart attacks) than those who didn't take statins. In fact, they were about half as likely to have such an event.

Those who stopped statin therapy were about 3 times more likely to die or have a heart attack than those who continued on statins. This finding was significant, in the statistical sense. Also, this group was about 1.7 times as likely to have an event as those who never took a statin, but this wasn't statistically significant, i.e. it might have occurred by chance alone.

There were some patients who started on statins during their hospitalization. They had a trend to having reduced cardiac event rates during the 30-day period compared with those who didn't take statins, but the difference wasn't statistically significant.

The timing of the first appearance of a difference between statin 'continuers' and 'discontinuers' -- 3 days - suggested the effect wasn't due to any statin effect on cholesterol levels, but was related to an action on the blood vessel lining cells.

What should we conclude?

These results show that patients on statin treatment going to hospital with acute coronary artery problems (chest pain at rest, or worsening chest pain) did significantly better than those not on statins. More importantly, those who discontinued their statin therapy after the onset of symptoms had a much poorer outcome -- three times as many cardiac events (death or heart attack) over the next 30 days.

The conclusions are fairly clear. With all drug therapy, benefits carry some risk of side effects. "There are no therapeutic roses without thorns". As with high blood pressure treatment, please don't stop taking your statin medication abruptly, except under the close supervision of your physician.