There is currently some concern about the long-term metabolic side effects of existing treatment regimens. Metabolic disorders, such as elevated blood lipids (including cholesterol) and a decreased sensitivity for insulin, which increases the chance of diabetes, pose an increased risk of cardiovascular disease. A large cohort study (the D:A:D study), executed worldwide, including in Dutch hospitals, has actually shown that the use of HIV combination therapy coincides with an increased risk of developing cardiovascular disease. A certain category of HIV inhibitors, the protease inhibitors, are particularly associated with elevated blood lipids. Results from the afore-mentioned worldwide study have recently indicated that in particular the use of protease inhibitors increases the risk of cardiovascular disease, which can to an important extent be explained by a change in the blood lipids caused by these medications. There are however some protease inhibitors, such as the recently developed drug atazanavir (ATV) and the protease inhibitor saquinavir (SQV) that has already been available for several years, which show no to only a little effect on blood lipids. SQV had the disadvantage of having to be dosed twice-daily, with many capsules (10-12 in total per day). Now that a new SQV tablet has been developed, the number of capsules to be taken per day has decreased dramatically (to only 4 in total per day) and moreover it has become possible in actual practice to take these capsules once per day. It is advisable, for both SQV and ATV, to combine the medication with one capsule of ritonavir (RTV), another protease inhibitor. This ensures that a reliable and effective level of SQV or ATV will be reached in the blood. RTV is associated with elevated blood lipids, but this effect is very limited in the low dosage that is used in combination with ATV or SQV. And as both SQV and ATV are combined with an equal amount of RTV, it is expected that their favorable effect on the blood lipids will be the same. For the same reason, the risk of cardiovascular disease is expected to be equally limited with the use of either of these two regimens.