Among the other big pharma conspiracy theory nonsense above:
The leading cause of death in North America is going to the hospital
There's obvious reverse-logic there: if you went to a hospital because of a health problem, if it's deadly you're more likely to die there. If you suffer of a serious condition you're more likely to visit hospitals frequently. It doesn't mean that the hospital, or medicine, are the cause of the illness. In general, proper treatment does indeed promote better outcomes. Before advances in medicine, and unfortunately it's still true in some places in the world, mortality was much higher. Other than infant and pregnancy-related deaths, many adults died in their 30s. Sometimes a tooth infection followed by sepsis is enough.
As for screening, it is indeed important to discover potentially life threatening diseases before organs are seriously affected. If you suffer from hematochromatosis, you want to know and adapt your diet before your liver is full if iron and you're poisoned. If you have a polyp or tumor, you want it checked and if it's considered threatening, removed, as fast as possible, before it grows or spreads elsewhere via metastasis. Blood and other tests and a biopsy are generally needed first and are part of prevention.