One way of doing things is to explain it the first time and then use the German acronym throughout the text, i.e.:Alters- und Hinterbliebenenversicherung (AHV)
[Old-age and survivors' insurance]
Old-age and survivors' insurance [Alters- und Hinterbliebenenversicherung (AHV)
That works as a general principle, but sometimes you find there is an official translation and an official acronym.
In this particular case, there is an official translation:
"Swiss Old Age and Survivors Insurance (OASI/DI - AHV/IV - AVS/AI)"http://www.eda.admin.ch/eda/en/home/reps/name...
So you could choose to use just the English:
"Old-age and survivors' insurance (OASI)"
The important things are to explain it clearly and be consistent throughout.
Just don't follow the 'how-not-to' example below, where the English acronym has been given as CCO and then the French CdC used -- aaargh:
"Central Compensation Office CCO
Welcome to the Central compensation Office CCO
The Central compensation Office CdC is a public service institution active in the domain of the 1st pillar’s social insurances, which includes the old-age and survivors’ insurance (OASI), the disability insurance (DI) and the loss of income allowance (APG). Its mission is also to enforce the international social security conventions. The CdC serves its insured persons and its partners."http://www.zas.admin.ch/index.html?lang=en&si...