English to German Medical Medical: Pharmaceuticals

Hi,

I am having a hard time understanding this sentence. This is about the comparison between a combination therapy of two different analgesic agents vs. each agent taken alone. The sentence in question is the second one, the first one is just to provide some more context. Is it just me, or does this sentence not make much sense, especially the grammatically questionable wording? Is there something missing between "relative" and "rates"? Should it say "relatively similar"?

"The safety outcomes evaluated were upper gastrointestinal events, myocardial infarction, stroke, renal failure (excluding chronic), congestive heart failure, intentional or accidental overdose, suicidal behaviour and mortality. **When comparing with past users, for most safety outcomes, current users of concomitant XXX and YYY had relative rates between those for current users of ibuprofen alone and paracetamol alone**."

This is my attempt so far:
"Beim Vergleich mit früheren Anwendern wiesen aktuelle Anwender der Kombination aus XXX und YYY hinsichtlich der meisten Sicherheitsergebnisse relativ gesehen ähnliche Inzidenzen auf wie aktuelle Anwender von als Monotherapie angewendetem XXX bzw. YYY."

My guess is that the sentence means to say: Relatively speaking, among the users of the combination, the rate of adverse events for each active substance was the same as the rate reported for each active substance when using it alone.

Thanks in advance for any input.