Have you been paying attention to shares of DaVita HealthCare (DVA) ? Shares have been on the move with the stock up 6.6% over the past month. The stock hit a new 52-week high of $151.05 in the previous session. DaVita HealthCare has gained 42.1% since the start of the year compared to the 8.6% move for the Zacks Medical sector and the 11.4% return for the Zacks Medical - Outpatient and Home Healthcare industry.What's Driving the Outperformance?The stock has an impressive record of positive earnings surpris ...