求翻译：然而，医疗消费为零是一种真实的医疗消费结果，而实际的医疗消费结果（Actual outcomes）不同于潜在结果（Potential outcomes），因此也就不存在样本选择偏差问题。是什么意思？

However, health care spending is zero is a real health care spending results, and actual results of the medical consumption (Actual outcomes) is different from the potential results (Potential outcomes), therefore there is no sample selection bias problem.

However, health care spending to zero is a real medical spending, while the actual results of medical consumer outcomes (Actual outcomes) different than the potential outcome (Potential outcomes) and consequently do not exist on sample selection bias.

However, the medical service expends for the zero is one kind of real medical expense result, but the actual medical expense result (Actual outcomes) is different with the latent result (Potential outcomes), therefore also does not have the sample choice deviation problem.

However, medical consumption to zero is a real medical consumption results, and the actual results of medical consumption (Actual outcomes) is different from the potential results (Potential outcomes), and therefore there is sample selection bias is not a problem.

However, medical consumption to zero is a real medical consumption results, and the actual results of medical consumption (Actual outcomes) is different from the potential results (Potential outcomes), and therefore there is sample selection bias is not a problem.