Creatine has shown to have positive effects in the clinical setting.  Creatine supplementation may reduce the chances of developing coronary heart disease (CHD).  Creatine supplementation is some cases has improved blood lipid profiles in subjects by increasing the ratio of high density lipoproteins (HDL) to low density lipoproteins (LDL).  Exercise along with modest creatine use may possibly prevent atherosclerosis that leads to CHD.

Earnest et al. (1998) state that mildly hypertriglyceremic patients that participated in 56 days of creatine supplementation showed noticeable decreases in total cholesterol (-6%) and triglycerides (-23%).

A study by Kreider et al. reported that subjects who creatine supplemented for 28 days increased HDL proteins by 13%, decreased LDL by 13%, and the ratio of total cholesterol to HDL by 7%.
 

Creatine may reduce the symptoms of neuromuscular diseases such as muscular dystrophy.  Many neuromuscular diseases result in decreases in intracellular PCr concentrations. Clinical studies have stated that strength improved considerably more for patients with muscular dystrophy who used creatine when compared to the non-users.

Felber et al. (2000) conducted a study implementing creatine treatment on a 9 year old boy with muscular dystrophy.  After 155 days of creatine use the patient's balance improved and he had increased the distance he could walk from 50 meters on a flat surface to 450 meters on an inclined surface.
 

Mitochondrial cytopathy is a condition that is known to reduce exercise capacity.  Creatine supplementation has been shown to be successful in treating patients with this condition.

It has also been suggested that oral ingestion of creatine has been successful in treating an inborn birth defect called guanidinoacetate-methyltranferase (GAMT) which causes creatine deficiencies in the brain leading to mental and muscular retardation.

Creatine supplementation has as been shown to decrease the symptoms of gyrate atrophy, a hereditary disease of the choroid and retina caused by creatine bio-synthesis.  Vannas-Sulonen et al. (1985) conducted a study requiring patients with gyrate atrophy to supplement creatine in small doses of 1.5g/day for a 5 year period.  Patients who used creatine showed more decreases in gyrate atrophy symptoms compared to non-users.  Results from a study conducted by Sipila et al. demonstrated that one year of creatine supplementation by patients with gyrate atrophy lead to a 43% increase in choroid and retina muscle fiber diameter.

Although these results seem very promising much more research still needs to be performed in regards to creatine supplementation and its effects on these conditions.