CVS climbs after raising annual profit forecast

** Shares of health insurer CVS Health CVS.N rise 5.1% to $109.70 premarket

** CVS expects annual adj. profit between $7.90 and $8.10 per share, compared with prior expectations of $7.30 to $7.50

** Co reports Q2 adj. profit of $2.58/shr vs analysts' average estimate of $1.85/shr, according to LSEG data

** CVS' Q2 revenue of $106.1 billion beats analysts' average expectation of $100.11 billion

** CVS' Aetna unit reports quarterly medical loss ratio, or the percentage of premiums spent on medical care, of 87.4% from 89.9% a year ago, compared to estimates of 90.03%

** Up to last close, stock up 31.6% YTD