For horses which are at risk of metabolic issues it is vital to ensure that their intake of sugars is closely monitored, their hooves are regularly trimmed and they get regular exercise.
Depending on how sensitive they are this can mean pulling them off pasture completely and feeding a low-sugar hay instead, or for the milder cases just using a grazing muzzle to limit the amount of grass they eat may be enough.
The type of trim the horse gets is also very important as small adjustments can make the world of difference.