NEW YORK (CNN/Money) – Fewer U.S. homeowners fell behind on their mortgage payments at the end of last year. The news, however, may not be as good as it appears.

That's in part because low interest rates and resilient housing prices provided a crutch to those who otherwise would have been limping financially.

The number of homeowners who were delinquent in making their mortgage payments fell in the fourth quarter of 2002 and the number of loans entering into foreclosure also slipped, according to a survey by the Mortgage Bankers Association (MBA) released Monday.

The seasonally adjusted overall delinquency rate for residential mortgage loans dropped to 4.53 percent, down from 4.66 percent in the third quarter of last year and down from 4.67 percent in the fourth quarter of 2001. A mortgage loan is considered delinquent if payment is 30 days or more past due.

The number of foreclosures started in the fourth quarter -- a leading indicator of trends in the market -- also slipped two basis points to 0.35 percent.

The number of foreclosures that were "in process" -- meaning they'd been started in other quarters and had yet to be resolved -- rose slightly, to a record 1.18 percent, up from 1.15 percent in the third quarter, and up from 1.04 percent in the fourth quarter of 2001.

How long a loan remains in the process of foreclosure varies from state to state. In some states, the process can take two years or more, while in others it can take as few as 90 days, said MBA chief economist Doug Duncan.

The surge in refinancing in 2002 may have accounted at least partially for the drop in delinquencies. "Refis can serve to mask at least some deterioration in mortgage histories," said Keith Gumbinger, vice president of HSH Associates, a publisher of mortgage and consumer loan information.

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With interest rates at historic lows, homeowners have had the option to refinance their existing mortgages to ones with lower monthly payments. So even if an existing mortgage had been delinquent, refinancing would make it current.

With housing prices still strong and homeowners' equity solid, lenders have been willing to offer refis (or work-out loans) to homeowners who may have fallen behind, said Mark Zandi, chief economist at Economy.com.

Also, refinancing an existing mortgage in a strong housing market -- where a homeowner's equity grows thanks to price appreciation -- can provide more of an immediate cash cushion in the event a homeowner loses a job. That reduces the chances that a homeowner would fall behind on mortgage payments while unemployed.

In terms of the decline in new foreclosures, record rates of personal bankruptcies may have had some effect and may continue to have an effect on the number of loans already in the process of foreclosure, a statistic that tends to lag changes in the economy. That's because in some states declaring personal bankruptcy can put the brakes on a foreclosure.

Generally speaking, several factors can affect delinquency and foreclosure rates going forward.

Employment is one key indicator. Improvements in the labor market could help lower the possibility of delinquency (and therefore the possibility of foreclosure).

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But at the same time, even if more jobs do become available and the economy improves, that could trigger rising interest rates, which would dampen the housing market.

What's more, if housing-price growth continues to slow as it has shown signs of doing, many homeowners may not see any significant growth in their equity, Zandi said. Those who bought at the top may even lose equity.

In such a case, there may be an increase in delinquencies. In a rising-rate environment, refinancing becomes less attractive when a homeowner is struggling to make ends meet. And lenders may be less accommodating if a homeowner with minimal or negative equity has fallen behind on the mortgage.

There's also the "seasoning effect" to consider, according to the MBA -- that is, a certain number of delinquencies is expected once a group of loans is a few years old. Given that low interest rates in 2002 also ushered in many first-time homebuyers and encouraged existing homeowners to trade up to more expensive homes, delinquency rates could climb as those loans season.