Months into the coronavirus pandemic, scientists have identified some clear patterns in which people who suffer from Covid-19 are most likely to die. Pre-existing medical conditions are one important factor. As of June 3, roughly nine in ten New Yorkers and Chicagoans who died of Covid-19 suffered from underlying chronic conditions. But those underlying conditions don’t affect everyone equally. They are much more prevalent among lower-income workers, according to researchers at the Centers for Disease Control and Prevention. Rates of chronic obstructive pulmonary disease, kidney disease and diabetes, for example, among the poorest 10 percent of New Yorkers are estimated to be more that 40 percent higher than the median rate.