Following her firm's May outpatient survey, Piper Jaffray analyst Sarah James is putting up an "early caution flag" for Q2 hospital earnings. The May outpatient survey indicates April was the peak, declining in May, with indications that June could be below April as well, James tells investors in a research note. After four months of increases, the outpatient survey declined 50 basis points from the April peak to 2.5% year-over-year same-hospital admissions in May, the analyst adds. She views the decline as concerning amid "tenuous" investor sentiment and "optimistic" Q2 expectations. Hospitals that Piper covers include Community Health (CYH), HCA Holdings (HCA), LifePoint (LPNT), Tenet (THC) and Universal Health (UHS).